* ``pull``, ``merge`` and ``push`` will no longer silently correct some repository index errors that occured as a result of the Weave disk format. Instead the ``reconcile`` command needs to be run to correct those problems if they exist (and it has been able to fix most such problems since bzr 0.8). Some new problems have been identified during this release and you should run ``bzr check`` once on every repository to see if you need to reconcile. If you cannot ``pull`` or ``merge`` from a remote repository due to mismatched parent errors - a symptom of index errors - you should simply take a full copy of that remote repository to a clean directory outside any local repositories, then run reconcile on it, and finally pull from it locally. (And naturally email the repositories owner to ask them to upgrade and run reconcile). (Robert Collins)
* ``VersionedFile.fix_parents`` has been removed as a harmful API. ``VersionedFile.join`` will no longer accept different parents on either side of a join - it will either ignore them, or error, depending on the implementation. See notes when upgrading for more information. (Robert Collins)