<section>
 <h1 class="contains-headerlink leafygreen-ui-41fr9s" weight="medium">
  Compatibility Changes in MongoDB 6.0
  <a class="headerlink leafygreen-ui-1kepx47" href="#compatibility-changes-in-mongodb-6.0" title="Permalink to this heading">
   <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
    <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
    </path>
    <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
    </path>
   </svg>
   <div class="css-1btu0w3 evvkmar0" id="compatibility-changes-in-mongodb-6.0">
   </div>
  </a>
 </h1>
 <div class="leafygreen-ui-a5yxub">
  <p class="css-1cmx2d4 ef7gu8j0">
   On this page
  </p>
  <ul class="css-1qb0mst ef7gu8j1">
   <li class="leafygreen-ui-1e7a0ei">
    <a class="lg-ui-0001 leafygreen-ui-e98ikf" href="#aggregation" target="_self">
     <span>
      Aggregation
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#change-streams" target="_self">
     <span>
      Change Streams
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#indexes" target="_self">
     <span>
      Indexes
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#legacy-mongo-shell-removed" target="_self">
     <span>
      Legacy
      <code class="css-1kekw28 e1wawog0">
       mongo
      </code>
      Shell Removed
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#platform-support" target="_self">
     <span>
      Platform Support
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#regular-expressions" target="_self">
     <span>
      Regular Expressions
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#removed-operators" target="_self">
     <span>
      Removed Operators
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#removed-options" target="_self">
     <span>
      Removed Options
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#removed-parameters" target="_self">
     <span>
      Removed Parameters
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#renamed-parameters" target="_self">
     <span>
      Renamed Parameters
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#ttl-expireafterseconds-behavior-when-set-to-nan" target="_self">
     <span>
      TTL
      <code class="css-1kekw28 e1wawog0">
       expireAfterSeconds
      </code>
      Behavior When Set to
      <code class="css-1kekw28 e1wawog0">
       NaN
      </code>
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#replica-sets" target="_self">
     <span>
      Replica Sets
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#security" target="_self">
     <span>
      Security
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#time-series-collections" target="_self">
     <span>
      Time Series Collections
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#general-changes" target="_self">
     <span>
      General Changes
     </span>
    </a>
   </li>
   <li class="leafygreen-ui-1jqtqlb">
    <a class="lg-ui-0001 leafygreen-ui-cpmeq5" href="#downgrade-considerations" target="_self">
     <span>
      Downgrade Considerations
     </span>
    </a>
   </li>
  </ul>
 </div>
 <p class="leafygreen-ui-1kp3ins">
  This page describes changes introduced in MongoDB 6.0 that can affect
compatibility with older versions of MongoDB.
 </p>
 <p class="leafygreen-ui-1kp3ins">
  MongoDB 6.0 is a
  <!-- -->
  Major
  <!-- -->
  Release, which means that it is supported for
both MongoDB Atlas and on-premises deployments. MongoDB 6.0 includes
changes introduced in MongoDB Rapid Releases 5.1, 5.2, and 5.3. This
page describes compatibility changes introduced in those Rapid Releases
and MongoDB 6.0.
 </p>
 <p class="leafygreen-ui-1kp3ins">
  To learn more about the differences between
  <!-- -->
  Major
  <!-- -->
  and Rapid releases,
see
  <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/versioning/#std-label-release-version-numbers">
   MongoDB Versioning
   <!-- -->
   .
  </a>
 </p>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Aggregation
   <a class="headerlink leafygreen-ui-1kepx47" href="#aggregation" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="aggregation">
    </div>
   </a>
  </h2>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    <code class="leafygreen-ui-1l06pbn">
     allowDiskUse
    </code>
    Changes
    <a class="headerlink leafygreen-ui-1kepx47" href="#allowdiskuse-changes" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="allowdiskuse-changes">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, pipeline stages that require more than 100
megabytes of memory to execute write temporary files to disk by
default. These temporary files last for the duration of the pipeline
execution and can influence storage space on your instance. In earlier
versions of MongoDB, you must pass
    <code class="leafygreen-ui-1l06pbn">
     { allowDiskUse: true }
    </code>
    to
individual
    <code class="leafygreen-ui-1l06pbn">
     find
    </code>
    and
    <code class="leafygreen-ui-1l06pbn">
     aggregate
    </code>
    commands to enable this
behavior.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    Individual
    <code class="leafygreen-ui-1l06pbn">
     find
    </code>
    and
    <code class="leafygreen-ui-1l06pbn">
     aggregate
    </code>
    commands can override the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#mongodb-parameter-param.allowDiskUseByDefault">
     <code class="leafygreen-ui-1l06pbn">
      allowDiskUseByDefault
     </code>
    </a>
    parameter by either:
   </p>
   <ul class="leafygreen-ui-rioki0">
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      Using
      <code class="leafygreen-ui-1l06pbn">
       { allowDiskUse: true }
      </code>
      to allow writing temporary files out
to disk when
      <code class="leafygreen-ui-1l06pbn">
       allowDiskUseByDefault
      </code>
      is set to
      <code class="leafygreen-ui-1l06pbn">
       false
      </code>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      Using
      <code class="leafygreen-ui-1l06pbn">
       { allowDiskUse: false }
      </code>
      to prohibit writing temporary files
out to disk when
      <code class="leafygreen-ui-1l06pbn">
       allowDiskUseByDefault
      </code>
      is set to
      <code class="leafygreen-ui-1l06pbn">
       true
      </code>
     </p>
    </li>
   </ul>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    <code class="leafygreen-ui-1l06pbn">
     $$SEARCH_META
    </code>
    Limitations
    <a class="headerlink leafygreen-ui-1kepx47" href="#--search_meta-limitations" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="--search_meta-limitations">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, the Atlas Search
    <code class="leafygreen-ui-1l06pbn">
     $$SEARCH_META
    </code>
    aggregation variable
can be used anywhere after a
    <a class="lg-ui-0001 leafygreen-ui-fgcsv5" href="https://www.mongodb.com/docs/atlas/atlas-search/aggregation-stages/search/#mongodb-pipeline-pipe.-search" target="_self">
     <span>
      <code class="leafygreen-ui-1l06pbn">
       $search
      </code>
     </span>
    </a>
    stage in any pipeline, but it
cannot be used after the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/aggregation/lookup/#mongodb-pipeline-pipe.-lookup">
     <code class="leafygreen-ui-1l06pbn">
      $lookup
     </code>
    </a>
    or
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/aggregation/unionWith/#mongodb-pipeline-pipe.-unionWith">
     <code class="leafygreen-ui-1l06pbn">
      $unionWith
     </code>
    </a>
    stage in
any pipeline. The
    <code class="leafygreen-ui-1l06pbn">
     $$SEARCH_META
    </code>
    aggregation variable cannot be used in any
subsequent stage after a
    <a class="lg-ui-0001 leafygreen-ui-fgcsv5" href="https://www.mongodb.com/docs/atlas/atlas-search/aggregation-stages/searchMeta/#mongodb-pipeline-pipe.-searchMeta" target="_self">
     <span>
      <code class="leafygreen-ui-1l06pbn">
       $searchMeta
      </code>
     </span>
    </a>
    stage.
   </p>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Change Streams
   <a class="headerlink leafygreen-ui-1kepx47" href="#change-streams" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="change-streams">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   Starting in MongoDB 5.3, during
   <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/sharding-balancer-administration/#std-label-range-migration-procedure">
    range migration
   </a>
   ,
   <a class="leafygreen-ui-tqgtui" href="/docs/manual/changeStreams/#std-label-changeStreams">
    change stream
   </a>
   events are not generated for updates to
   <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/glossary/#std-term-orphaned-document">
    orphaned documents
    <!-- -->
    .
   </a>
  </p>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Filters
    <a class="headerlink leafygreen-ui-1kepx47" href="#filters" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="filters">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, whenever possible,
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/changeStreams/#std-label-change-stream-modify-output">
     match filters
    </a>
    are applied to change streams earlier
than in prior releases. This improves performance. However, when a
filter is narrowly defined, an earlier match may cause an operation that
succeeds in prior versions to fail in 6.0.
   </p>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Indexes
   <a class="headerlink leafygreen-ui-1kepx47" href="#indexes" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="indexes">
    </div>
   </a>
  </h2>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Last Remaining Shard Key Index Cannot be Dropped Inadvertently
    <a class="headerlink leafygreen-ui-1kepx47" href="#last-remaining-shard-key-index-cannot-be-dropped-inadvertently" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="last-remaining-shard-key-index-cannot-be-dropped-inadvertently">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, passing
    <code class="leafygreen-ui-1l06pbn">
     "*"
    </code>
    to
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/dropIndexes/#mongodb-dbcommand-dbcmd.dropIndexes">
     <code class="leafygreen-ui-1l06pbn">
      dropIndexes
     </code>
    </a>
    or
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/db.collection.dropIndexes/#mongodb-method-db.collection.dropIndexes">
     <code class="leafygreen-ui-1l06pbn">
      db.collection.dropIndexes()
     </code>
    </a>
    drops all indexes
    <strong>
     except
    </strong>
    for the
    <code class="leafygreen-ui-1l06pbn">
     _id
    </code>
    index and the last remaining shard key index, if one
exists. Attempts to explicitly drop the last remaining shard key index
raise an error.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Existing Indexes Can Be Dropped During an Index Build
    <a class="headerlink leafygreen-ui-1kepx47" href="#existing-indexes-can-be-dropped-during-an-index-build" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="existing-indexes-can-be-dropped-during-an-index-build">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.2, you can use
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/dropIndexes/#mongodb-dbcommand-dbcmd.dropIndexes">
     <code class="leafygreen-ui-1l06pbn">
      dropIndexes
     </code>
    </a>
    or
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/db.collection.dropIndexes/#mongodb-method-db.collection.dropIndexes">
     <code class="leafygreen-ui-1l06pbn">
      db.collection.dropIndexes()
     </code>
    </a>
    to drop existing indexes on the
same collection even if there is an index build in progress. In earlier
versions, attempting to drop a different index during an in-progress
index build results in a
    <code class="leafygreen-ui-1l06pbn">
     BackgroundOperationInProgressForNamespace
    </code>
    error.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    2dsphere Document Index Keys
    <a class="headerlink leafygreen-ui-1kepx47" href="#2dsphere-document-index-keys" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="2dsphere-document-index-keys">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    To prevent out of memory errors,
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#mongodb-parameter-param.indexMaxNumGeneratedKeysPerDocument">
     <code class="leafygreen-ui-1l06pbn">
      indexMaxNumGeneratedKeysPerDocument
     </code>
    </a>
    limits the maximum
number of
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/geospatial-queries/#std-label-geo-2dsphere">
     2dsphere index keys
    </a>
    generated for a
single document.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    See
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#mongodb-parameter-param.indexMaxNumGeneratedKeysPerDocument">
     <code class="leafygreen-ui-1l06pbn">
      indexMaxNumGeneratedKeysPerDocument
     </code>
     .
    </a>
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Index Key Format
    <a class="headerlink leafygreen-ui-1kepx47" href="#index-key-format" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="index-key-format">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, a change to the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/index-unique/#std-label-index-type-unique">
     unique index
    </a>
    key format was introduced. If you create a unique
index in MongoDB 6.0, the index won't work with MongoDB versions earlier
than 5.3.2 or 5.0.7.
   </p>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Legacy
   <code class="leafygreen-ui-1l06pbn">
    mongo
   </code>
   Shell Removed
   <a class="headerlink leafygreen-ui-1kepx47" href="#legacy-mongo-shell-removed" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="legacy-mongo-shell-removed">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   The
   <code class="leafygreen-ui-1l06pbn">
    mongo
   </code>
   shell is removed from MongoDB 6.0. The
replacement is
   <a class="lg-ui-0001 leafygreen-ui-fgcsv5" href="https://www.mongodb.com/docs/mongodb-shell/#mongodb-binary-bin.mongosh" target="_self">
    <span>
     <code class="leafygreen-ui-1l06pbn">
      mongosh
     </code>
     .
    </span>
   </a>
  </p>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Platform Support
   <a class="headerlink leafygreen-ui-1kepx47" href="#platform-support" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="platform-support">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   Starting in MongoDB 5.1.2 the following platforms are no longer
supported:
  </p>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Community Edition
    <a class="headerlink leafygreen-ui-1kepx47" href="#community-edition" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="community-edition">
     </div>
    </a>
   </h3>
   <ul class="leafygreen-ui-rioki0">
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <span class="leafygreen-ui-vm4wms" tabindex="0">
       RHEL
      </span>
      -72-s390x
     </p>
    </li>
   </ul>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Regular Expressions
   <a class="headerlink leafygreen-ui-1kepx47" href="#regular-expressions" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="regular-expressions">
    </div>
   </a>
  </h2>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    <code class="leafygreen-ui-1l06pbn">
     $regex
    </code>
    Find Queries No Longer Ignore Invalid Regex
    <a class="headerlink leafygreen-ui-1kepx47" href="#-regex-find-queries-no-longer-ignore-invalid-regex" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="-regex-find-queries-no-longer-ignore-invalid-regex">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.1, invalid
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/query/regex/#mongodb-query-op.-regex">
     <code class="leafygreen-ui-1l06pbn">
      $regex options
     </code>
    </a>
    options are no longer ignored. This change makes
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/query/regex/#mongodb-query-op.-regex">
     <code class="leafygreen-ui-1l06pbn">
      $regex options
     </code>
    </a>
    more consistent with
the use of
    <code class="leafygreen-ui-1l06pbn">
     $regex
    </code>
    in the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/aggregate/#mongodb-dbcommand-dbcmd.aggregate">
     <code class="leafygreen-ui-1l06pbn">
      aggregate
     </code>
    </a>
    command and
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/tutorial/project-fields-from-query-results/#std-label-projection">
     projection
    </a>
    queries.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    <code class="leafygreen-ui-1l06pbn">
     $regex
    </code>
    Schema Validation Error Behavior
    <a class="headerlink leafygreen-ui-1kepx47" href="#-regex-schema-validation-error-behavior" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="-regex-schema-validation-error-behavior">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.1, if a collection has
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/schema-validation/specify-query-expression-rules/#std-label-schema-validation-query-expression">
     schema validation
    </a>
    rules that contain invalid
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/query/regex/#mongodb-query-op.-regex">
     <code class="leafygreen-ui-1l06pbn">
      $regex options
     </code>
    </a>
    the server:
   </p>
   <ul class="leafygreen-ui-rioki0">
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      Prevents all insert and update operations until the schema validation
rules containing the invalid regex pattern are modified with the
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/collMod/#mongodb-dbcommand-dbcmd.collMod">
       <code class="leafygreen-ui-1l06pbn">
        collMod
       </code>
      </a>
      command.
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      Writes a warning error to the
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/program/mongod/#mongodb-binary-bin.mongod">
       <code class="leafygreen-ui-1l06pbn">
        mongod
       </code>
      </a>
      log file.
     </p>
    </li>
   </ul>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Removed Operators
   <a class="headerlink leafygreen-ui-1kepx47" href="#removed-operators" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="removed-operators">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   Starting in MongoDB 5.1, these legacy query operators are removed:
  </p>
  <div class="leafygreen-ui-skkc39" tabindex="0">
   <table class="leafygreen-ui-hr8lsv">
    <thead class="leafygreen-ui-a9ho40">
     <tr data-testid="leafygreen-ui-header-row">
      <th class="leafygreen-ui-1trtg6r" role="columnheader" scope="col">
       <div class="leafygreen-ui-ui0te9">
        <div>
         Removed Operator
        </div>
       </div>
      </th>
      <th class="leafygreen-ui-13uteka" role="columnheader" scope="col">
       <div class="leafygreen-ui-ui0te9">
        <div>
         Alternative
        </div>
       </div>
      </th>
     </tr>
    </thead>
    <tbody>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $comment
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.comment/#mongodb-method-cursor.comment">
          <code class="leafygreen-ui-1l06pbn">
           cursor.comment()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $explain
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.explain/#mongodb-method-cursor.explain">
          <code class="leafygreen-ui-1l06pbn">
           cursor.explain()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $hint
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.hint/#mongodb-method-cursor.hint">
          <code class="leafygreen-ui-1l06pbn">
           cursor.hint()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $max
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.max/#mongodb-method-cursor.max">
          <code class="leafygreen-ui-1l06pbn">
           cursor.max()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $maxTimeMS
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.maxTimeMS/#mongodb-method-cursor.maxTimeMS">
          <code class="leafygreen-ui-1l06pbn">
           cursor.maxTimeMS()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $min
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.min/#mongodb-method-cursor.min">
          <code class="leafygreen-ui-1l06pbn">
           cursor.min()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $orderby
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.sort/#mongodb-method-cursor.sort">
          <code class="leafygreen-ui-1l06pbn">
           cursor.sort()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $query
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         See
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/js-cursor/#std-label-doc-cursor-methods">
          Cursor Methods
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $returnKey
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.returnKey/#mongodb-method-cursor.returnKey">
          <code class="leafygreen-ui-1l06pbn">
           cursor.returnKey()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         $showDiskLoc
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/cursor.showRecordId/#mongodb-method-cursor.showRecordId">
          <code class="leafygreen-ui-1l06pbn">
           cursor.showRecordId()
          </code>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <code class="leafygreen-ui-1l06pbn">
          db.getLastError()
         </code>
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         See
         <a class="lg-ui-0001 leafygreen-ui-fgcsv5" href="#std-label-legacy-op-codes-removed" target="_self">
          <span>
           Legacy Opcodes Removed
          </span>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <code class="leafygreen-ui-1l06pbn">
          db.getLastErrorObj()
         </code>
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         See
         <a class="lg-ui-0001 leafygreen-ui-fgcsv5" href="#std-label-legacy-op-codes-removed" target="_self">
          <span>
           Legacy Opcodes Removed
          </span>
         </a>
        </div>
       </div>
      </td>
     </tr>
     <tr class="leafygreen-ui-15dvrnp">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <code class="leafygreen-ui-1l06pbn">
          getLastError
         </code>
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         See
         <a class="lg-ui-0001 leafygreen-ui-fgcsv5" href="#std-label-legacy-op-codes-removed" target="_self">
          <span>
           Legacy Opcodes Removed
          </span>
         </a>
        </div>
       </div>
      </td>
     </tr>
    </tbody>
   </table>
  </div>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Removed Options
   <a class="headerlink leafygreen-ui-1kepx47" href="#removed-options" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="removed-options">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   MongoDB 6.0 removes the
   <code class="leafygreen-ui-1l06pbn">
    --cpu
   </code>
   <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/program/mongod/#mongodb-binary-bin.mongod">
    <code class="leafygreen-ui-1l06pbn">
     mongod
    </code>
   </a>
   option.
  </p>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Removed Parameters
   <a class="headerlink leafygreen-ui-1kepx47" href="#removed-parameters" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="removed-parameters">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   MongoDB 6.0 removes the following server parameters:
  </p>
  <div class="leafygreen-ui-skkc39" tabindex="0">
   <table class="leafygreen-ui-hr8lsv">
    <colgroup>
     <col style="width:25%"/>
     <col style="width:75%"/>
    </colgroup>
    <thead class="leafygreen-ui-a9ho40">
     <tr data-testid="leafygreen-ui-header-row">
      <th class="leafygreen-ui-1trtg6r" role="columnheader" scope="col">
       <div class="leafygreen-ui-ui0te9">
        <div>
         Removed Parameter
        </div>
       </div>
      </th>
      <th class="leafygreen-ui-13uteka" role="columnheader" scope="col">
       <div class="leafygreen-ui-ui0te9">
        <div>
         Description
        </div>
       </div>
      </th>
     </tr>
    </thead>
    <tbody>
     <tr class="">
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/program/mongod/#std-option-mongod.--tlsFIPSMode">
          <code class="leafygreen-ui-1l06pbn">
           --tlsFIPSMode
          </code>
         </a>
        </div>
       </div>
      </td>
      <td class="leafygreen-ui-1drjk7h">
       <div class="leafygreen-ui-1n4j8xf">
        <div>
         <p class="leafygreen-ui-1kp3ins">
          This option is removed from the MongoDB Community Edition. It
is available in MongoDB Enterprise edition.
         </p>
         <p class="leafygreen-ui-1kp3ins">
          FIPS was not a supported feature in MongoDB Community Edition.
If your installation made use of FIPS anyway, you will need to
          <a class="leafygreen-ui-tqgtui" href="/docs/manual/tutorial/configure-ssl/">
           reconfigure your TLS/SSL connections
          </a>
          before upgrading.
         </p>
        </div>
       </div>
      </td>
     </tr>
    </tbody>
   </table>
  </div>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Renamed Parameters
   <a class="headerlink leafygreen-ui-1kepx47" href="#renamed-parameters" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="renamed-parameters">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   Starting in MongoDB 6.0, the following parameters have been renamed:
  </p>
  <ul class="leafygreen-ui-rioki0">
   <li class="leafygreen-ui-d7p7b6">
    <p class="leafygreen-ui-1kp3ins">
     <code class="leafygreen-ui-1l06pbn">
      wiredTigerConcurrentReadTransactions
     </code>
     is now
     <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#mongodb-parameter-param.storageEngineConcurrentReadTransactions">
      <code class="leafygreen-ui-1l06pbn">
       storageEngineConcurrentReadTransactions
      </code>
     </a>
    </p>
   </li>
   <li class="leafygreen-ui-d7p7b6">
    <p class="leafygreen-ui-1kp3ins">
     <code class="leafygreen-ui-1l06pbn">
      wiredTigerConcurrentWriteTransactions
     </code>
     is now
     <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#mongodb-parameter-param.storageEngineConcurrentWriteTransactions">
      <code class="leafygreen-ui-1l06pbn">
       storageEngineConcurrentWriteTransactions
      </code>
     </a>
    </p>
   </li>
  </ul>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   TTL
   <code class="leafygreen-ui-1l06pbn">
    expireAfterSeconds
   </code>
   Behavior When Set to
   <code class="leafygreen-ui-1l06pbn">
    NaN
   </code>
   <a class="headerlink leafygreen-ui-1kepx47" href="#ttl-expireafterseconds-behavior-when-set-to-nan" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="ttl-expireafterseconds-behavior-when-set-to-nan">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   Setting
   <a class="leafygreen-ui-tqgtui" href="/docs/manual/tutorial/expire-data/#std-label-ttl-collections">
    TTL
   </a>
   <code class="leafygreen-ui-1l06pbn">
    expireAfterSeconds
   </code>
   to
   <code class="leafygreen-ui-1l06pbn">
    NaN
   </code>
   experiences a behavior change from MongoDB 4.4 to MongoDB 6.0 that
affects initial sync from MongoDB 4.4 and earlier and
   <a class="lg-ui-0001 leafygreen-ui-fgcsv5" href="https://www.mongodb.com/docs/database-tools/mongorestore/#mongodb-binary-bin.mongorestore" target="_self">
    <span>
     <code class="leafygreen-ui-1l06pbn">
      mongorestore
     </code>
    </span>
   </a>
   from MongoDB 4.4 and earlier. Performing
any of those actions causes an
   <code class="leafygreen-ui-1l06pbn">
    expireAfterSeconds
   </code>
   of
   <code class="leafygreen-ui-1l06pbn">
    NaN
   </code>
   to be
treated as an
   <code class="leafygreen-ui-1l06pbn">
    expireAfterSeconds
   </code>
   of
   <code class="leafygreen-ui-1l06pbn">
    0
   </code>
   . Immediate document
expiration may occur as a result.
  </p>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Replica Sets
   <a class="headerlink leafygreen-ui-1kepx47" href="#replica-sets" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="replica-sets">
    </div>
   </a>
  </h2>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Assert Cluster Wide Write Concern is Set When Starting or Adding Shard
    <a class="headerlink leafygreen-ui-1kepx47" href="#assert-cluster-wide-write-concern-is-set-when-starting-or-adding-shard" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="assert-cluster-wide-write-concern-is-set-when-starting-or-adding-shard">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.1, when starting, restarting or adding a
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/sharded-cluster-components/#std-label-sharding-shards">
     shard server
    </a>
    with
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/sh.addShard/#mongodb-method-sh.addShard">
     <code class="leafygreen-ui-1l06pbn">
      sh.addShard()
     </code>
    </a>
    the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/setDefaultRWConcern/#std-label-set_global_default_write_concern">
     Cluster Wide Write Concern (CWWC)
    </a>
    must be set.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    If the
    <code class="leafygreen-ui-1l06pbn">
     CWWC
    </code>
    is not set and the shard is configured
such that the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/write-concern/#std-label-write-concern">
     default write concern
    </a>
    is
    <code class="leafygreen-ui-1l06pbn">
     { w : 1 }
    </code>
    the shard server will fail to start or be added
and returns an error.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    See
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/mongodb-defaults/#std-label-default-wc-formula">
     default write concern calculations
    </a>
    for
details on how the default write concern is calculated.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    <code class="leafygreen-ui-1l06pbn">
     rs.reconfig
    </code>
    Cluster Wide Write Concern Validation
    <a class="headerlink leafygreen-ui-1kepx47" href="#rs.reconfig-cluster-wide-write-concern-validation" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="rs.reconfig-cluster-wide-write-concern-validation">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.1, you must set the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/setDefaultRWConcern/#std-label-set_global_default_write_concern">
     Cluster Wide Write Concern (CWWC)
    </a>
    prior to issuing any
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/rs.reconfig/#mongodb-method-rs.reconfig">
     <code class="leafygreen-ui-1l06pbn">
      reconfigs
     </code>
    </a>
    that would otherwise change the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/write-concern/#std-label-write-concern">
     default write concern
    </a>
    of the new
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/glossary/#std-term-replica-set">
     replica set
    </a>
    member.
   </p>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Security
   <a class="headerlink leafygreen-ui-1kepx47" href="#security" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="security">
    </div>
   </a>
  </h2>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Intra-Cluster Authentication
    <a class="headerlink leafygreen-ui-1kepx47" href="#intra-cluster-authentication" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="intra-cluster-authentication">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.3,
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/security-scram/#std-label-authentication-scram-sha-1">
     SCRAM-SHA-1
    </a>
    cannot be used for intra-cluster authentication. Only
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/security-scram/#std-label-authentication-scram-sha-256">
     SCRAM-SHA-256
    </a>
    is supported.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    In previous MongoDB versions, SCRAM-SHA-1 and SCRAM-SHA-256 can both be
used for intra-cluster authentication, even if SCRAM is not explicitly
enabled.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    FIPS Mode Defaults SCRAM-SHA-1 Authentication to Off
    <a class="headerlink leafygreen-ui-1kepx47" href="#fips-mode-defaults-scram-sha-1-authentication-to-off" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="fips-mode-defaults-scram-sha-1-authentication-to-off">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.1, instances running in
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/tutorial/configure-fips/#std-label-fips-overview">
     FIPS mode
    </a>
    have the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#std-label-authentication-parameters">
     SCRAM-SHA-1 authentication mechanism
    </a>
    disabled by default. You can enable the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#std-label-authentication-parameters">
     SCRAM-SHA-1 authentication
mechanism
    </a>
    with the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#std-label-set-parameter-authenticationMechanisms-code">
     setParameter.authenticationMechanisms
    </a>
    command.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    This change will not affect drivers which target MongoDB
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/setFeatureCompatibilityVersion/#mongodb-dbcommand-dbcmd.setFeatureCompatibilityVersion">
     <code class="leafygreen-ui-1l06pbn">
      setFeatureCompatibilityVersion
     </code>
    </a>
    4.0+.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    OCSP Must be Enabled
    <a class="headerlink leafygreen-ui-1kepx47" href="#ocsp-must-be-enabled" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="ocsp-must-be-enabled">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, if
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#mongodb-parameter-param.ocspEnabled">
     <code class="leafygreen-ui-1l06pbn">
      ocspEnabled
     </code>
    </a>
    is set to
    <code class="leafygreen-ui-1l06pbn">
     true
    </code>
    during
initial sync, all nodes must be able to reach the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/security-transport-encryption/#std-label-ocsp-support">
     OCSP
    </a>
    responder.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    If a member fails in the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/replica-states/#mongodb-replstate-replstate.STARTUP2">
     <code class="leafygreen-ui-1l06pbn">
      STARTUP2
     </code>
    </a>
    state, set
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/parameters/#mongodb-parameter-param.tlsOCSPVerifyTimeoutSecs">
     <code class="leafygreen-ui-1l06pbn">
      tlsOCSPVerifyTimeoutSecs
     </code>
    </a>
    to a value that is less than
    <code class="leafygreen-ui-1l06pbn">
     5
    </code>
    .
   </p>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Time Series Collections
   <a class="headerlink leafygreen-ui-1kepx47" href="#time-series-collections" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="time-series-collections">
    </div>
   </a>
  </h2>
  <div class="leafygreen-ui-1sjx7ru" role="note">
   <h2 class="leafygreen-ui-29m78u">
    Warning
   </h2>
   <div class="leafygreen-ui-9mycqc">
    <p class="leafygreen-ui-1kp3ins">
     If you create a sharded
     <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/timeseries-collections/#std-label-manual-timeseries-collection">
      time series collection
     </a>
     in MongoDB 5.1 or greater, downgrading
to a version older than MongoDB 5.0.4 will result in data loss.
    </p>
    <p class="leafygreen-ui-1kp3ins">
     Before downgrading to a version older than 5.0.4, drop all sharded
time series collections.
    </p>
   </div>
  </div>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Secondary Indexes on Time Series Collections
    <a class="headerlink leafygreen-ui-1kepx47" href="#secondary-indexes-on-time-series-collections" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="secondary-indexes-on-time-series-collections">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    If there are
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/glossary/#std-term-secondary-index">
     secondary indexes
    </a>
    on
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/timeseries-collections/#std-label-manual-timeseries-collection">
     time
series collections
    </a>
    and you need to
downgrade the feature compatibility version (fCV), you must first drop
any secondary indexes that are incompatible with the downgraded fCV.
For more information, see
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/setFeatureCompatibilityVersion/#mongodb-dbcommand-dbcmd.setFeatureCompatibilityVersion">
     <code class="leafygreen-ui-1l06pbn">
      setFeatureCompatibilityVersion
     </code>
     .
    </a>
   </p>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   General Changes
   <a class="headerlink leafygreen-ui-1kepx47" href="#general-changes" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
     <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="general-changes">
    </div>
   </a>
  </h2>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Deprecations
    <a class="headerlink leafygreen-ui-1kepx47" href="#deprecations" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="deprecations">
     </div>
    </a>
   </h3>
   <div class="leafygreen-ui-skkc39" tabindex="0">
    <table class="leafygreen-ui-hr8lsv">
     <colgroup>
      <col style="width:20%"/>
      <col style="width:80%"/>
     </colgroup>
     <thead class="leafygreen-ui-a9ho40">
      <tr data-testid="leafygreen-ui-header-row">
       <th class="leafygreen-ui-1trtg6r" role="columnheader" scope="col">
        <div class="leafygreen-ui-ui0te9">
         <div>
          Deprecated
         </div>
        </div>
       </th>
       <th class="leafygreen-ui-13uteka" role="columnheader" scope="col">
        <div class="leafygreen-ui-ui0te9">
         <div>
          Description
         </div>
        </div>
       </th>
      </tr>
     </thead>
     <tbody>
      <tr class="">
       <td class="leafygreen-ui-1drjk7h">
        <div class="leafygreen-ui-1n4j8xf">
         <div>
          <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/db.collection.reIndex/#mongodb-method-db.collection.reIndex">
           <code class="leafygreen-ui-1l06pbn">
            db.collection.reIndex()
           </code>
          </a>
         </div>
        </div>
       </td>
       <td class="leafygreen-ui-1drjk7h">
        <div class="leafygreen-ui-1n4j8xf">
         <div>
          The
          <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/db.collection.reIndex/#mongodb-method-db.collection.reIndex">
           <code class="leafygreen-ui-1l06pbn">
            db.collection.reIndex()
           </code>
          </a>
          method is deprecated in
MongoDB v6.0.
         </div>
        </div>
       </td>
      </tr>
      <tr class="">
       <td class="leafygreen-ui-1drjk7h">
        <div class="leafygreen-ui-1n4j8xf">
         <div>
          <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/reIndex/#mongodb-dbcommand-dbcmd.reIndex">
           <code class="leafygreen-ui-1l06pbn">
            reIndex
           </code>
          </a>
         </div>
        </div>
       </td>
       <td class="leafygreen-ui-1drjk7h">
        <div class="leafygreen-ui-1n4j8xf">
         <div>
          The
          <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/reIndex/#mongodb-dbcommand-dbcmd.reIndex">
           <code class="leafygreen-ui-1l06pbn">
            reIndex
           </code>
          </a>
          command is deprecated in MongoDB v6.0.
         </div>
        </div>
       </td>
      </tr>
      <tr class="">
       <td class="leafygreen-ui-1drjk7h">
        <div class="leafygreen-ui-1n4j8xf">
         <div>
          Simple Network Management Protocol (SNMP)
         </div>
        </div>
       </td>
       <td class="leafygreen-ui-1drjk7h">
        <div class="leafygreen-ui-1n4j8xf">
         <div>
          <p class="leafygreen-ui-1kp3ins">
           Starting in MongoDB 6.0, SNMP is deprecated and will be removed in the
next release. To monitor your deployment, use
           <a class="lg-ui-0001 leafygreen-ui-fgcsv5" href="https://www.mongodb.com/docs/ops-manager/current/" target="_self">
            <span>
             MongoDB Ops Manager
            </span>
           </a>
           .
          </p>
         </div>
        </div>
       </td>
      </tr>
     </tbody>
    </table>
   </div>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    <code class="leafygreen-ui-1l06pbn">
     $mod
    </code>
    Error Behavior
    <a class="headerlink leafygreen-ui-1kepx47" href="#-mod-error-behavior" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="-mod-error-behavior">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.1 (and 5.0.4), the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/query/mod/#mongodb-query-op.-mod">
     <code class="leafygreen-ui-1l06pbn">
      $mod
     </code>
    </a>
    operator returns an error if the
    <code class="leafygreen-ui-1l06pbn">
     divisor
    </code>
    or
    <code class="leafygreen-ui-1l06pbn">
     remainder
    </code>
    values
evaluate to certain values. See
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/query/mod/#std-label-mod-behavior">
     $mod behavior
     <!-- -->
     .
    </a>
   </p>
   <span class="leafygreen-ui-1qnjd6d" id="std-label-legacy-op-codes-removed">
   </span>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Legacy Opcodes Removed
    <a class="headerlink leafygreen-ui-1kepx47" href="#legacy-opcodes-removed" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="legacy-opcodes-removed">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    MongoDB 6.0 removes support for the following legacy opcodes and
database commands:
   </p>
   <ul class="leafygreen-ui-rioki0">
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-insert">
       OP_INSERT
      </a>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-delete">
       OP_DELETE
      </a>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-update">
       OP_UPDATE
      </a>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-kill-cursors">
       OP_KILL_CURSORS
      </a>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-get-more">
       OP_GET_MORE
      </a>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-query">
       OP_QUERY
      </a>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <code class="leafygreen-ui-1l06pbn">
       getLastError
      </code>
     </p>
    </li>
   </ul>
   <div class="leafygreen-ui-1sjx7ru" role="note">
    <h2 class="leafygreen-ui-29m78u">
     Warning
    </h2>
    <h3 class="leafygreen-ui-144d5kf">
     <strong>
      Upgrade Drivers
     </strong>
    </h3>
    <div class="leafygreen-ui-9mycqc">
     <p class="leafygreen-ui-1kp3ins">
      To avoid disruption due to the removal of these opcodes,
      <strong>
       upgrade your
driver to the latest version
      </strong>
      .
     </p>
    </div>
   </div>
   <p class="leafygreen-ui-1kp3ins">
    If you attempt to connect to a MongoDB 3.4 or older
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/program/mongod/#mongodb-binary-bin.mongod">
     <code class="leafygreen-ui-1l06pbn">
      mongod
     </code>
    </a>
    instance with a MongoDB 5.1 or newer
    <code class="leafygreen-ui-1l06pbn">
     mongo
    </code>
    shell, you
will receive an error message like the following:
   </p>
   <script class="structured_data" type="application/ld+json">
    {"@context":"https://schema.org","@type":"SoftwareSourceCode","codeSampleType":"code snippet","text":"Connection handshake failed. Is your mongod 3.4 or older?\n:: caused by :: network error while attempting to run command\n'isMaster' on host '127.0.0.1:27017'"}
   </script>
   <div class="css-1lju8ps">
    <div class="leafygreen-ui-196mwvg">
     <div class="leafygreen-ui-1jheeh3">
      <pre class="leafygreen-ui-1453az5" tabindex="-1"><code class="lg-highlight-hljs-light none leafygreen-ui-9ybzas"><table class="leafygreen-ui-1tr4g10"><tbody><tr class=""><td class="leafygreen-ui-7razhx">Connection handshake failed. Is your mongod 3.4 or older?</td></tr><tr class=""><td class="leafygreen-ui-7razhx">:: caused by :: network error while attempting to run command</td></tr><tr class=""><td class="leafygreen-ui-7razhx">'isMaster' on host '127.0.0.1:27017'</td></tr></tbody></table></code></pre>
     </div>
    </div>
   </div>
   <section>
    <h4 class="contains-headerlink leafygreen-ui-1vzlt5f">
     mongod Responses to Legacy Opcodes
     <a class="headerlink leafygreen-ui-1kepx47" href="#mongod-responses-to-legacy-opcodes" title="Permalink to this heading">
      <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
       <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
       </path>
       <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
       </path>
      </svg>
      <div class="css-1btu0w3 evvkmar0" id="mongod-responses-to-legacy-opcodes">
      </div>
     </a>
    </h4>
    <p class="leafygreen-ui-1kp3ins">
     Since MongoDB 3.6, MongoDB drivers have used
     <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/mongodb-wire-protocol/#std-label-wire-op-msg">
      OP_MSG
     </a>
     instead of
     <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-query">
      OP_QUERY
     </a>
     and the other legacy opcodes
and commands.
    </p>
    <p class="leafygreen-ui-1kp3ins">
     Starting in MongoDB 6.0:
    </p>
    <ul class="leafygreen-ui-rioki0">
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/program/mongod/#mongodb-binary-bin.mongod">
        <code class="leafygreen-ui-1l06pbn">
         mongod
        </code>
       </a>
       will close the connection and will not respond to:
      </p>
      <ul class="leafygreen-ui-rioki0">
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-insert">
          OP_INSERT
         </a>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-delete">
          OP_DELETE
         </a>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-update">
          OP_UPDATE
         </a>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-kill-cursors">
          OP_KILL_CURSORS
         </a>
        </p>
       </li>
      </ul>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/program/mongod/#mongodb-binary-bin.mongod">
        <code class="leafygreen-ui-1l06pbn">
         mongod
        </code>
       </a>
       will keep the connection open and return an error for:
      </p>
      <ul class="leafygreen-ui-rioki0">
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         The
         <code class="leafygreen-ui-1l06pbn">
          getLastError
         </code>
         database command
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-get-more">
          OP_GET_MORE
         </a>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-query">
          OP_QUERY
         </a>
         finds
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         Most
         <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-query">
          OP_QUERY
         </a>
         <span class="leafygreen-ui-vm4wms" tabindex="0">
          RPC
         </span>
         command messages
        </p>
       </li>
      </ul>
     </li>
    </ul>
    <div class="leafygreen-ui-15mdk4" role="note">
     <h2 class="leafygreen-ui-6n7b7d">
      Note
     </h2>
     <h3 class="leafygreen-ui-144d5kf">
      <strong>
       OP_QUERY RPC Commands
      </strong>
     </h3>
     <div class="leafygreen-ui-9mycqc">
      <p class="leafygreen-ui-1kp3ins">
       The
       <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-query">
        OP_QUERY
       </a>
       <span class="leafygreen-ui-vm4wms" tabindex="0">
        RPC
       </span>
       protocol may be used with the following commands:
      </p>
      <ul class="leafygreen-ui-rioki0">
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          _isSelf
         </code>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          authenticate
         </code>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          buildinfo
         </code>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          buildInfo
         </code>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          hello
         </code>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          ismaster
         </code>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          isMaster
         </code>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          saslContinue
         </code>
        </p>
       </li>
       <li class="leafygreen-ui-d7p7b6">
        <p class="leafygreen-ui-1kp3ins">
         <code class="leafygreen-ui-1l06pbn">
          saslStart
         </code>
        </p>
       </li>
      </ul>
      <p class="leafygreen-ui-1kp3ins">
       All other commands will be rejected if issued as
       <a class="leafygreen-ui-tqgtui" href="/docs/manual/legacy-opcodes/#std-label-wire-op-query">
        OP_QUERY
        <!-- -->
        .
       </a>
      </p>
     </div>
    </div>
    <span class="leafygreen-ui-1qnjd6d" id="std-label-6.0-js-engine-change">
    </span>
   </section>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Removed Deprecated Array and String Functions for Server-Side JavaScript
    <a class="headerlink leafygreen-ui-1kepx47" href="#removed-deprecated-array-and-string-functions-for-server-side-javascript" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="removed-deprecated-array-and-string-functions-for-server-side-javascript">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    MongoDB 6.0 upgrades the internal JavaScript engine used for
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/server-side-javascript/#std-label-server-side-javascript">
     server-side JavaScript
    </a>
    ,
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/aggregation/accumulator/#mongodb-group-grp.-accumulator">
     <code class="leafygreen-ui-1l06pbn">
      $accumulator
     </code>
    </a>
    ,
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/aggregation/function/#mongodb-expression-exp.-function">
     <code class="leafygreen-ui-1l06pbn">
      $function
     </code>
    </a>
    , and
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/query/where/#mongodb-query-op.-where">
     <code class="leafygreen-ui-1l06pbn">
      $where
     </code>
    </a>
    expressions and from MozJS-60 to MozJS-91. Several deprecated,
non-standard array and string functions that existed in MozJS-60 are
removed in MozJS-91.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    For the complete list of removed array and string functions, see the
next sections on this page.
   </p>
   <div class="leafygreen-ui-15mdk4" role="note">
    <h2 class="leafygreen-ui-6n7b7d">
     Note
    </h2>
    <h3 class="leafygreen-ui-144d5kf">
     <strong>
      Only Static Functions are Removed
     </strong>
    </h3>
    <div class="leafygreen-ui-9mycqc">
     <p class="leafygreen-ui-1kp3ins">
      Only
      <em>
       static
      </em>
      JavaScript functions are removed.
      <em>
       Prototype function
      </em>
      equivalents of the removed functions can still be used.
     </p>
     <p class="leafygreen-ui-1kp3ins">
      For example:
     </p>
     <ul class="leafygreen-ui-rioki0">
      <li class="leafygreen-ui-d7p7b6">
       <p class="leafygreen-ui-1kp3ins">
        <code class="leafygreen-ui-1l06pbn">
         Array.concat(&lt;array1&gt;, &lt;array2&gt;)
        </code>
        is a static function and no
longer works in MongoDB 6.0.
       </p>
      </li>
      <li class="leafygreen-ui-d7p7b6">
       <p class="leafygreen-ui-1kp3ins">
        <code class="leafygreen-ui-1l06pbn">
         &lt;array1&gt;.concat(&lt;array2&gt;)
        </code>
        is a prototype function and still
works in MongoDB 6.0.
       </p>
      </li>
     </ul>
     <p class="leafygreen-ui-1kp3ins">
      This behavior applies to both removed array and removed string
functions.
     </p>
    </div>
   </div>
   <section>
    <h4 class="contains-headerlink leafygreen-ui-1vzlt5f">
     Removed Array Functions
     <a class="headerlink leafygreen-ui-1kepx47" href="#removed-array-functions" title="Permalink to this heading">
      <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
       <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
       </path>
       <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
       </path>
      </svg>
      <div class="css-1btu0w3 evvkmar0" id="removed-array-functions">
      </div>
     </a>
    </h4>
    <p class="leafygreen-ui-1kp3ins">
     Starting in MongoDB 6.0, the following array functions are removed and
cannot be used in server-side JavaScript with
     <code class="leafygreen-ui-1l06pbn">
      $accumulator
     </code>
     ,
     <code class="leafygreen-ui-1l06pbn">
      $function
     </code>
     , and
     <code class="leafygreen-ui-1l06pbn">
      $where
     </code>
     expressions:
    </p>
    <ul class="leafygreen-ui-rioki0">
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.concat
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.every
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.filter
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.forEach
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.indexOf
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.join
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.lastIndexOf
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.map
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.pop
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.push
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.reduce
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.reduceRight
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.reverse
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.shift
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.slice
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.some
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.sort
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.splice
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        Array.unshift
       </code>
      </p>
     </li>
    </ul>
   </section>
   <section>
    <h4 class="contains-headerlink leafygreen-ui-1vzlt5f">
     Removed String Functions
     <a class="headerlink leafygreen-ui-1kepx47" href="#removed-string-functions" title="Permalink to this heading">
      <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
       <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
       </path>
       <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
       </path>
      </svg>
      <div class="css-1btu0w3 evvkmar0" id="removed-string-functions">
      </div>
     </a>
    </h4>
    <p class="leafygreen-ui-1kp3ins">
     Starting in MongoDB 6.0, the following array functions are removed and
cannot be used in server-side JavaScript with
     <code class="leafygreen-ui-1l06pbn">
      $accumulator
     </code>
     ,
     <code class="leafygreen-ui-1l06pbn">
      $function
     </code>
     , and
     <code class="leafygreen-ui-1l06pbn">
      $where
     </code>
     expressions:
    </p>
    <ul class="leafygreen-ui-rioki0">
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.charAt
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.charCodeAt
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.concat
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.contains
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.endsWith
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.includes
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.indexOf
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.lastIndexOf
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.localeCompare
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.match
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.normalize
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.replace
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.search
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.slice
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.split
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.startsWith
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.substr
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.substring
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.toLocaleLowerCase
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.toLocaleUpperCase
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.toLowerCase
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.toUpperCase
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.trim
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.trimLeft
       </code>
      </p>
     </li>
     <li class="leafygreen-ui-d7p7b6">
      <p class="leafygreen-ui-1kp3ins">
       <code class="leafygreen-ui-1l06pbn">
        String.trimRight
       </code>
      </p>
     </li>
    </ul>
   </section>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Default
    <code class="leafygreen-ui-1l06pbn">
     db.stats()
    </code>
    Settings
    <a class="headerlink leafygreen-ui-1kepx47" href="#default-db.stats---settings" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="default-db.stats---settings">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/dbStats/#mongodb-dbcommand-dbcmd.dbStats">
     <code class="leafygreen-ui-1l06pbn">
      dbStats
     </code>
    </a>
    command and the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/db.stats/#mongodb-method-db.stats">
     <code class="leafygreen-ui-1l06pbn">
      db.stats()
     </code>
    </a>
    method only report free space assigned to
collections if the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/dbStats/#std-label-dbStats-freeStorage">
     freeStorage
    </a>
    parameter is
set to 1.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Index Filters and Collations
    <a class="headerlink leafygreen-ui-1kepx47" href="#index-filters-and-collations" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="index-filters-and-collations">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, an index filter uses the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/collation/#std-label-collation">
     collation
    </a>
    previously set using the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/planCacheSetFilter/#mongodb-dbcommand-dbcmd.planCacheSetFilter">
     <code class="leafygreen-ui-1l06pbn">
      planCacheSetFilter
     </code>
    </a>
    command.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 8.0, use query settings instead of adding
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/query-plans/#std-label-index-filters">
     index filters
    </a>
    . Index filters are deprecated
starting in MongoDB 8.0.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    Query settings have more functionality than index filters. Also, index
filters aren't persistent and you cannot easily create index filters for
all cluster nodes. To add query settings and explore examples, see
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/setQuerySettings/#mongodb-dbcommand-dbcmd.setQuerySettings">
     <code class="leafygreen-ui-1l06pbn">
      setQuerySettings
     </code>
     .
    </a>
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Arrays in Collections and Views with
    <code class="leafygreen-ui-1l06pbn">
     distinct
    </code>
    Command
    <a class="headerlink leafygreen-ui-1kepx47" href="#arrays-in-collections-and-views-with-distinct-command" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="arrays-in-collections-and-views-with-distinct-command">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/distinct/#mongodb-dbcommand-dbcmd.distinct">
     <code class="leafygreen-ui-1l06pbn">
      distinct
     </code>
    </a>
    command returns the
same results for collections and
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/views/#std-label-views-landing-page">
     views
    </a>
    when
using arrays.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    See
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/distinct/#std-label-distinct-arrays-in-collections-and-views">
     Arrays in Collections and Views
     <!-- -->
     .
    </a>
   </p>
   <span class="leafygreen-ui-1qnjd6d" id="std-label-6.0-downgrade-considerations">
   </span>
  </section>
 </section>
 <section>
  <h2 class="contains-headerlink leafygreen-ui-19f71ei" weight="medium">
   Downgrade Considerations
   <a class="headerlink leafygreen-ui-1kepx47" href="#downgrade-considerations" title="Permalink to this heading">
    <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
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     </path>
     <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
     </path>
    </svg>
    <div class="css-1btu0w3 evvkmar0" id="downgrade-considerations">
    </div>
   </a>
  </h2>
  <p class="leafygreen-ui-1kp3ins">
   The following sections provide information for removing
backward-incompatible features from your deployment. If you are
downgrading from MongoDB
   <!-- -->
   6.0
   <!-- -->
   to an earlier version, review the
following sections to ensure that your deployment runs successfully
after downgrading.
  </p>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Clustered Collections
    <a class="headerlink leafygreen-ui-1kepx47" href="#clustered-collections" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="clustered-collections">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.3, if you are using
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/clustered-collections/#std-label-clustered-collections">
     clustered collections
    </a>
    , you must drop those collections before you can
downgrade to an earlier MongoDB version.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    User Write Blocking
    <a class="headerlink leafygreen-ui-1kepx47" href="#user-write-blocking" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="user-write-blocking">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, if you need to downgrade the feature
compatibility version, ensure you disable cluster-to-cluster replication
and user write blocking.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    See
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/setFeatureCompatibilityVersion/#std-label-setFeatureCompatibilityVersion-user-write-blocking">
     Cluster-to-Cluster Sync and User Write Blocking
     <!-- -->
     .
    </a>
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Time Series Collections
    <a class="headerlink leafygreen-ui-1kepx47" href="#time-series-collections-1" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="time-series-collections-1">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    You must drop time series collections before downgrading:
   </p>
   <ul class="leafygreen-ui-rioki0">
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      MongoDB 6.0 or later to MongoDB 5.0.7 or earlier.
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      MongoDB 5.3 to MongoDB 5.0.5 or earlier.
     </p>
    </li>
   </ul>
   <p class="leafygreen-ui-1kp3ins">
    See
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/timeseries-collections/#std-label-manual-timeseries-collection">
     Time Series Collections
     <!-- -->
     .
    </a>
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Cluster Parameters
    <a class="headerlink leafygreen-ui-1kepx47" href="#cluster-parameters" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="cluster-parameters">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, ensure that all
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/setClusterParameter/#mongodb-dbcommand-dbcmd.setClusterParameter">
     <code class="leafygreen-ui-1l06pbn">
      setClusterParameter
     </code>
    </a>
    operations have completed.
    <span class="leafygreen-ui-vm4wms" tabindex="0">
     fCV
    </span>
    downgrade cannot occur successfully if there are any ongoing
    <code class="leafygreen-ui-1l06pbn">
     setClusterParameter
    </code>
    operations on sharded clusters.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    SELinux Policy Data
    <a class="headerlink leafygreen-ui-1kepx47" href="#selinux-policy-data" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="selinux-policy-data">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.1, you must run the following command from the
directory into which the SELinux policy was previously cloned before you
can downgrade to an earlier MongoDB version:
   </p>
   <script class="structured_data" type="application/ld+json">
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     <div class="leafygreen-ui-yzcs8i">
      <pre class="leafygreen-ui-1q4bxgx" tabindex="-1"><code class="lg-highlight-hljs-light bash leafygreen-ui-9ybzas"><table class="leafygreen-ui-1tr4g10"><tbody><tr class=""><td class="leafygreen-ui-7razhx">sudo make uninstall</td></tr></tbody></table></code></pre>
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  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Key Management Interoperability Protocol (KMIP) Settings
    <a class="headerlink leafygreen-ui-1kepx47" href="#key-management-interoperability-protocol--kmip--settings" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="key-management-interoperability-protocol--kmip--settings">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, the default KMIP protocol version is 1.2. To use KMIP
version 1.0 or 1.1, use the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/configuration-options/#mongodb-setting-security.kmip.useLegacyProtocol">
     <code class="leafygreen-ui-1l06pbn">
      useLegacyProtocol
     </code>
    </a>
    setting.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 5.3 Enterprise, if you are using the following KMIP
settings, you must remove them from the configuration file before you
can downgrade to an earlier MongoDB version:
   </p>
   <ul class="leafygreen-ui-rioki0">
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/configuration-options/#mongodb-setting-security.kmip.keyStatePollingSeconds">
       <code class="leafygreen-ui-1l06pbn">
        security.kmip.keyStatePollingSeconds
       </code>
      </a>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/configuration-options/#mongodb-setting-security.kmip.activateKeys">
       <code class="leafygreen-ui-1l06pbn">
        security.kmip.activateKeys
       </code>
      </a>
     </p>
    </li>
   </ul>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Time-based Retention of Change Streams Pre- and Post-Image Collections
    <a class="headerlink leafygreen-ui-1kepx47" href="#time-based-retention-of-change-streams-pre--and-post-image-collections" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="time-based-retention-of-change-streams-pre--and-post-image-collections">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, if you are using
    <code class="leafygreen-ui-1l06pbn">
     changeStreamOptions.preAndPostImages.expireAfterSeconds
    </code>
    to control
time-based retention of
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/method/db.collection.watch/#std-label-db.collection.watch-change-streams-pre-and-post-images-example">
     change streams pre- and post-image collections
    </a>
    , you
must ensure there are no active
    <code class="leafygreen-ui-1l06pbn">
     setClusterParameter
    </code>
    operations when
downgrading.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Audit Log Encryption Settings
    <a class="headerlink leafygreen-ui-1kepx47" href="#audit-log-encryption-settings" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="audit-log-encryption-settings">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0 Enterprise, if you are using audit log
encryption, you must remove the following settings from the
configuration file before you can downgrade to an earlier MongoDB
version:
   </p>
   <ul class="leafygreen-ui-rioki0">
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/configuration-options/#mongodb-setting-auditLog.auditEncryptionKeyIdentifier">
       <code class="leafygreen-ui-1l06pbn">
        auditLog.auditEncryptionKeyIdentifier
       </code>
      </a>
     </p>
    </li>
    <li class="leafygreen-ui-d7p7b6">
     <p class="leafygreen-ui-1kp3ins">
      <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/configuration-options/#mongodb-setting-auditLog.localAuditKeyFile">
       <code class="leafygreen-ui-1l06pbn">
        auditLog.localAuditKeyFile
       </code>
      </a>
     </p>
    </li>
   </ul>
   <p class="leafygreen-ui-1kp3ins">
    Existing encrypted audit logs remain encrypted, and you can keep any
procedures you have developed for storage and processing of encrypted
logs.
   </p>
   <p class="leafygreen-ui-1kp3ins">
    See
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/core/security-encryption-at-rest/#std-label-security-encryption-at-rest-audit-log">
     Audit Log
     <!-- -->
     .
    </a>
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Change Streams with Document Pre- and Post-Images
    <a class="headerlink leafygreen-ui-1kepx47" href="#change-streams-with-document-pre--and-post-images" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="change-streams-with-document-pre--and-post-images">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    Starting in MongoDB 6.0, if you are using document pre- and post-images
for
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/change-events/#std-label-change-stream-output">
     change streams
    </a>
    , you must disable
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/collMod/#std-label-collMod-change-stream-pre-and-post-images">
     changeStreamPreAndPostImages
    </a>
    for each collection using
the
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/command/collMod/#mongodb-dbcommand-dbcmd.collMod">
     <code class="leafygreen-ui-1l06pbn">
      collMod
     </code>
    </a>
    command before you can downgrade to an earlier
MongoDB version.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Change Streams with Expanded Events
    <a class="headerlink leafygreen-ui-1kepx47" href="#change-streams-with-expanded-events" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="change-streams-with-expanded-events">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    If your application uses change streams, ensure that it does not require the
    <code class="leafygreen-ui-1l06pbn">
     showExpandedEvents
    </code>
    option, which will not be available after downgrade.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    LDAP with
    <code class="leafygreen-ui-1l06pbn">
     srv:
    </code>
    and
    <code class="leafygreen-ui-1l06pbn">
     srv_raw:
    </code>
    <a class="headerlink leafygreen-ui-1kepx47" href="#ldap-with-srv--and-srv_raw-" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="ldap-with-srv--and-srv_raw-">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    If your cluster's configuration is using the new
    <code class="leafygreen-ui-1l06pbn">
     "srv:"
    </code>
    or
    <code class="leafygreen-ui-1l06pbn">
     "srv_raw:"
    </code>
    URL types in its LDAP configuration, it will be unable
to restart after a downgrade. Remove the new URL types from your
cluster's configuration before downgrading.
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Collections with Encrypted Fields
    <a class="headerlink leafygreen-ui-1kepx47" href="#collections-with-encrypted-fields" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="collections-with-encrypted-fields">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    You must drop collections that use encrypted fields before you
can complete the fCV downgrade. The downgrade will not complete
if there are collections using
    <code class="leafygreen-ui-1l06pbn">
     encryptedFields
    </code>
    .
   </p>
  </section>
  <section>
   <h3 class="contains-headerlink leafygreen-ui-15ajumo" weight="medium">
    Create New Documents Operation Using
    <code class="leafygreen-ui-1l06pbn">
     $densify
    </code>
    <a class="headerlink leafygreen-ui-1kepx47" href="#create-new-documents-operation-using--densify" title="Permalink to this heading">
     <svg aria-label="Link Icon" class="leafygreen-ui-a30zj9" fill="none" height="12" role="img" viewbox="0 0 16 16" width="12" xmlns="http://www.w3.org/2000/svg">
      <path d="M6.039 9.953a3.596 3.596 0 0 1-.327-.38l1.45-1.445a1.553 1.553 0 0 0 2.496.423l2.885-2.87a1.57 1.57 0 0 0 .01-2.213 1.553 1.553 0 0 0-2.203-.01l-.379.377A.995.995 0 0 1 8.56 3.83a1.005 1.005 0 0 1 .006-1.418l.38-.377a3.542 3.542 0 0 1 5.024.023 3.58 3.58 0 0 1-.022 5.047l-2.884 2.871a3.542 3.542 0 0 1-5.025-.022Z" fill="currentColor">
      </path>
      <path d="M9.961 6.047c.12.12.228.248.327.38l-1.45 1.445a1.553 1.553 0 0 0-2.496-.423l-2.885 2.87a1.57 1.57 0 0 0-.01 2.213 1.553 1.553 0 0 0 2.203.01l.379-.377a.995.995 0 0 1 1.411.006 1.005 1.005 0 0 1-.006 1.418l-.38.377a3.542 3.542 0 0 1-5.024-.023 3.58 3.58 0 0 1 .022-5.047l2.884-2.871a3.542 3.542 0 0 1 5.025.022Z" fill="currentColor">
      </path>
     </svg>
     <div class="css-1btu0w3 evvkmar0" id="create-new-documents-operation-using--densify">
     </div>
    </a>
   </h3>
   <p class="leafygreen-ui-1kp3ins">
    If your application uses
    <a class="leafygreen-ui-tqgtui" href="/docs/manual/reference/operator/aggregation/densify/#mongodb-pipeline-pipe.-densify">
     <code class="leafygreen-ui-1l06pbn">
      $densify
     </code>
    </a>
    to create documents that
fill gaps, add missing values, or populate your data with specified
range of values, remove the
    <code class="leafygreen-ui-1l06pbn">
     $densify
    </code>
    stage from your aggregation
pipeline before downgrading. The
    <code class="leafygreen-ui-1l06pbn">
     $densify
    </code>
    stage is only available in
version 5.1 and later.
   </p>
  </section>
 </section>
</section>
