This is rather official, and cool that we are hearing this now. This will according to rumors be a compilation of updated rules for Planetstrike, Stronghold Assault, and Cities of Death. Sounds like fun!
via Warhammer 40,000 Facebook
https://www.facebook.com/Warhammer-40000-1575682476085719
Coming soon, a new supplement for Warhammer 40,000.