You can download the rules from here.
Army lists available here.
Some key changes included now:
- Fixed some typos.
- Add Ultra-Heavy tanks and AT guns.
- Increased PEN values for many weapons.
- Expanded the Close Combat section (as it was in v2.0).
- Added Chemical Attacks optional rules.
- Added Supports rules (been wanting to do this for a while).
- Includes supports for irregulars and regulars.
- Revamped rules for Drones.
- Revamped rules for Close Air Support (CAS).
- Updates rules for Smoke Dischargers (moved from army lists into the vehicle special rules).
- Added Back Blast Area weapons special rule.
- Added Anti Aircraft Gun and Anti Aircraft Missile weapons special rules.
I think that covers it - plus the changes from v3.0 (changes to advanced armour, advance ammo, etc.). Pictures of the sheets below.