The new version uses most of the features included in GeneXus 15; just to name a few the whole site is Full Response.
There is a new Theme based on the Carmine. You can configure the desired colors using the Palette object; notice this Wiki is generated green; the Community Wiki is generated red.
The Recent pages section was completely redesigned, please take a look !
A new Table of content (TOC) Page type is introduced; you can check a sample here.
Check the new Builtin Templates added in this version
New relations between page have been added to model Page Branching and Page Precedence.
The FCKEditor can be extended adding extra plugins; check this article to enable the autosave option.