What comes to my mind as first (some of it was already mentioned)
Basic "history" facts and diplomacy:
There is whole new house named Gallia (so lot of new corporations and unlawful faction introduced) whose navy invaded Sirius sector (with some lame excuse, real reason is they need resources and very secret rumours also say that their high command or maybe king himself are infected by nomads), crushed Kusari Navy in Taus and forced Kusari to be friends with them. Consequently there was regime change in Kusari so they are democratic republic now. Old Kaigun went to exile in Bretonia (so there was/is new faction Kusari Exiles). Then Gallia invaded Bretonia, where they conquered some bordering systems (Tau-31, Tau-23, Edinburg, Lewis...) and mainly also almost have Leeds (there is still fight on surface of planet Leeds though). This forced Bretonia to blow up jumpgate connecting Leeds with New London. Gallia also declared war to Liberty so Liberty and Bretonia are allied against Gallia.
Rheinlad is (still) at war with Liberty, but was forced to blow up gates connecting Hamburg with Bering and Hudson because was (by lore) loosing (their economy is kinda crippled).
Kusari is now at war with nobody.
Apart from wars - Rheinland kicked Interspace Commerce entirely (but from what I heard they should be allowed to return soon).
Corsairs still feed themself by selling artifacts.
Outacasts still feed themself by selling cardamine (and pissing everything in Liberty with indie capital ship swarms from time to time).
Liberty navy boarded IMG station in Magellan (ooRPly it was set up by IMG, in fact they just handed over the station because of Gallia forces appeared even in this system, difficult to explain shortly).
Stuff:
Player controlled bases (PoBs - player owned bases) which can have cargo storages, weapon platforms and also can produce cloaks, jumpdrives, hyperspace survey modules (it makes coordinates for jumping with jumpdrives) and docking modules (allows fighters to dock on bigger player ships like liners or carriers).
Scanners now really are different (they have difference in range and cargo scanning range).
Ships have swapable engines so you can have for example civilian ships with Rheinland green engine. There is lot of it with lot of colours, but be careful, not all of them are compatible (for example Gallic engines on Sirian ships). Nice eye candy, see here.