A customer hit a bug where they had upgraded the Review Board package,

but not the database, and had run a management command that found the

new rbintegrations package and tried to install it, triggering an

early database upgrade. This was quite problematic, and caused a lot of

confusion while trying to diagnose a separate upgrade problem.
To avoid this, and potentially other problems, we no longer load any

extensions if the Review Board version stored in the database does not

match the package version. Instead, extensions will only load if the

version matches. This lets us avoid these early migrations prior to a

database upgrade.
The one caveat is that this won't solve the problem if syncdb and

evolve are run in separate sessions (by invoking manage.py twice,

for instance). syncdb will set the new database version, meaning that

evolve is free to load extensions again. This is only really an issue

during development, since rb-site upgrade runs these in the same

session.
Part of this will be addressed in some longer-term Django Evolution

work, which will be providing a command similar to modern Django's

migrate command, where everything can be done all at once.

Shorter-term, an upcoming change will add an upgrade command to

manage.py.

Reproduced the original problem by upgrading the Review Board package

and running a management command. Saw that the database upgrade did not

trigger until I explicitly performed it.