At Gen Con new battle group models were for presale, for Ogrth and Cygnar. Khador got a new army too.
The key info can be found:
Warmachine – MKIV – Privateer Press
The original announcment was Big News, and was an intresting read about the plans that Privateer press have for the game. Its quite long!
WARMACHINE: BIG NEWS! – Privateer Press
As of today the Beta of the Mk4 App is on iOS and coming to Android very soon.