user19338: I replaced my bitcoind from v0.11.2 to v0.12.1. Then I found "UpdateTip: 6 of last 100 blocks have unexpected version" in debug.log. This error occurs at new block generation. Can I ignore this? If not, how can I fix it?
I downloaded the new bitcond from 
https://github.com/btcdrak/bitcoin/releases
https://github.com/btcdrak/bitcoin/releases/download/v0.12.1-addrindex/bitcoin-0.12.1-addrindex-linux64.tar.gz

user3697: Yes. You can ignore this.
This means that some miners have mined (still compatible) blocks with a version number unknown to Bitcoin Core.
Generally this indicates that some miners have mined blocks that signal non Bitcoin Core compatible soft- or hard-forks. Very likely a 2MB hardfork after BIP109 implemented by Bitcoin Classic.

19338: <p>I replaced my bitcoind from v0.11.2 to v0.12.1. Then I found "UpdateTip: 6 of last 100 blocks have unexpected version" in debug.log. This error occurs at new block generation. Can I ignore this? If not, how can I fix it?</p>

<p>I downloaded the new bitcond from </p>

<p><a href="https://github.com/btcdrak/bitcoin/releases" rel="noreferrer">https://github.com/btcdrak/bitcoin/releases</a>
<a href="https://github.com/btcdrak/bitcoin/releases/download/v0.12.1-addrindex/bitcoin-0.12.1-addrindex-linux64.tar.gz" rel="noreferrer">https://github.com/btcdrak/bitcoin/releases/download/v0.12.1-addrindex/bitcoin-0.12.1-addrindex-linux64.tar.gz</a></p>
 3697: <p><strong>Yes. You can ignore this.</strong></p>

<p>This means that some miners have mined (still compatible) blocks with a version number unknown to Bitcoin Core.</p>

<p>Generally this indicates that some miners have mined blocks that signal non Bitcoin Core compatible soft- or hard-forks. Very likely a 2MB hardfork after BIP109 implemented by Bitcoin Classic.</p>
