This is one of the biggest updates we did so far. Mostly due the C++ 11 ABI change within gcc. It is recommended to rebuild your AUR packages for this ABI.
With this we finally dropping KDE4 for good. All users of this desktop should either switch over to Plasma 5 or any other maintained desktop, like LXQt.
So what changed? We have now Plasma 5.5 with all its goodies, updated Mesa and LibreOffice. Also we changed our profiles structure for our manjaro-tools. Maintainers of Manjaro install-medias should adopt.
Archlinux upstream fixes are now from: Sun Dec 13 09:19:23 CET 2015.