Hi,
the tag creation and the release of the beta of Applications/16.04 will happen
this Wednesday, March 23. After that, we will remove the current translations
of Applications/15.12 from the stable branches and copy the files of
Applications/16.04 from trunk to stable, as usual.

So, if you updated your translations in stable (for Applications/15.12) but
not in trunk, it's time to update it now!

You can always recover the old translations, as they will copied to another
location (and even if they were deleted, they are in Subversion anyway), but
it's definitely easier now. Lokalize can help, and it could be also a good
time to reevaluate posummit, which avoids the problem of switching branches
and the risk of losing translations.

Ciao
-- 
Luigi