You might have noted that
biblatex has been updated to version 2.3 and the documentation documentation says:
If an entry in the revision history states that a feature has been improved or extended, this indicates a modification which either does not affect the syntax and behavior of the package or is syntactically backwards compatible (such as the addition of an optional argument to an existing command). Entries stating that a feature has been modified, renamed, or removed demand attention. They indicate a modification which may require changes to existing styles or documents in some, hopefully rare, cases.