Overwatch is not an official rule, its optional. Be careful not to confuse the “Expanded Rules” (optional) with the new Revised rules update (which is really only 3 or 4 rules adjustements).
3 new extensions added to Axis and Allies MINIATURAS v3.0 Vassal
-Reserves extension : New pieces, new countries, new armies…
-Rotated boards extension: Now we can choose rotated boards in our battles.
-Scenarios Campaigns extension: Complete North African Campaign pre set defined.