Manga Studio 5 EX will not be available until summer of 2013. The current upgrade/full version is Manga Studio 5 which has the features of Manga Studio 4 EX plus a new interface. The main feature with 5 EX coming out in the summer is having multiple pages to work with.
In fact Manga Studio 5 is an English port of Clip Studio Paint Pro. Celsys is phasing out Comic Studio which the earlier Manga Studio was based on.
So, if I order the upgrade now (I'm not terribly concerned about having the multi-page feature) will I have to order the upgrade for $50 or the full for $80? I don't mind spending the extra money, I'd just like to know.