The easiest one is the weapon range changes. The Icestorm one has been out forever. When playing 2.5, we've made use of every somewhat confirms change out there. The Gencon Seminar gave us heaps more. Note in particular Burst 2 Forward observer. Here are the rest of the changes, as far as I know (yet):
1. If target above 20, add number above 20 to roll. If you reach 20 it is a crit.
2. Forward observer is burst 2 and can now mark target. If 'targeted' then +3 for allies to hit this turn
3. Loss of lieutenant everyone irregular for turn and then new lieutenant appointed automatically.
4. Retreat is 75%. Everyone becomes irregular and must take a Wip check. Cannot advance/shoot if fail. Can only move to retreat. If pass move normal. If have V courage then immune. Religious/Remote presence ignore check.
5.Veteran means stay regular during retreat / loss of lieutenant. Morat skill also has that effect.
6. Breaker pistol is effectively AP for BTS but only one roll not two like viral.
7. Multispectoral Visors - MSV 1 now gets to apply -3 to TO camo and ODD. MSV3 now has to make a discover roll to spot, though auto-passes.
8. Camo surprise shot now becomes a face to face roll with -3 modifier to the unit being shot at.
9. No matter how many modifiers, these are capped at +12 or -12.
Here is what we know about CC:
1. +1 dice per ally in base to base.
2. Close combat chart. Reactive player pick one first, then active. Choose one skill level on chart, they do not stack.
3. Assault allows a model to move-move to contact target in CC if the enemy is in line of fire. -3 to CC value.
I haven't included stuff on the change to always allowing reactions, changes to infiltrations/AD, and so on, as I am not sure how this will work in practice. If it does get confirmed, send me a link!
Thanks for reading.