1. A method comprising: accessing, at a machine, an original instance comprising: first content comprising transaction data and master data; a plurality of first sources, wherein a first source of the plurality of first sources comprises a first set of executable instructions; and a first data dictionary comprising first mapping data that associates information in an application to an underlying database; generating, at the machine, a shadow copy of the original instance, the shadow copy comprising first shadow copy content, the first shadow copy content comprising shadow transaction data equivalent to the transaction data; receiving, at the machine, a first change to the original instance comprising a transaction data update; applying, at the machine, the first change to the original instance to generate a changed original instance comprising second content, a plurality of second sources, and a second data dictionary, the second content comprising the transaction data update; applying, at the machine, the first change to the shadow copy to generate a changed shadow copy, the changed shadow copy comprising changed shadow copy content comprising the transaction data update; receiving, at the machine, a new instance comprising a first difference relative to the changed original instance, wherein the first difference is relative to the second source or relative to the second data dictionary; and modifying the changed original instance to generate a second changed original instance, wherein the second changed original instance comprises a second difference relative to the changed shadow copy, and wherein the second difference is equivalent to the first difference.