Here KDE 4.13.2 comes. Big release changelogs could be read here:
http://www.kde.org/announcements/4.12/http://www.kde.org/announcements/4.13/
Critical things you should be aware of:
1. Nepomuk is gone, it's superseeded by Baloo. Nepomuk libraries
are still here, though, but they do rely on Baloo internally.
2. kdnssd was renamed to zeroconf-ioslave;
3. kwallet was renamed to kwalletmanager;
4. Akonadi cache will be rebuilt; this could result in change
of PIM folder indexes, which in turn could mess up your
mail filters - beware.
5. ... a lot of other little problems that always happen during
update.
Things could be broken for a day or two in subtle ways - don't
hesistate on reporting them!
