The usual system updates plus:
Fix QT apps not starting anymore
Cannot mix incompatible Qt library (5.15.2) with this library (5.15.3)
This is the error. To fix it simply go to Add/Remove Software, click the top right gear icon and refresh the database. After that reinstall the package qt5-styleplugins. Search for it, click it, then click reinstall. Should fix it.
Mate-HUD: not upgrading!
Recently the people behind mate-HUD, the HUD we use for TROMjaro, pushed an update that seems to force an internal theme to be used. This theme is not that good at all, and makes it less functional. See more here https://github.com/ubuntu-mate/mate-hud/issues/52
We decided to not update it for now, until we can fix this ourselves. So we recommend you do not upgrade it from the AUR.