Edit: Corrected some info.
We got the rest of the Besma dungeons, the town Altera where there's two new dungeons, new quests and items that come with those dungeons of course, level cap was raised to 35 plus the guild system. A guild is created by using a guild founding deed, which can be bought from Aranka, costs 1.5 million ED (cannot be traded unless you seal it).
Founded guild WTFish. Still trying to figure out how this thing works, but apparently the guild can level up. The guild gets xp when guildies get xp, too low level guildies in relation to guild level cannot contribute to guild xp. The guild gets skill points, or GSP, upon level up, which guildmaster can allocate on guild skills. The first skills are mostly stat boosts, but there's also one which boosts xp gain when playing in dungeons with guildies.
There are a few guild related items that Aranka can craft:
Guild Expansion Right: increases max amount of guild members by 10 (starting amount is 20, can be boosted up to 100). Guildmaster and guild manager can use this.
Horn of Forget: with this you can cancel a guild skill and get back the GSP from that skill. Only guildmaster can use this.
Great Gnosis Blessing: gives 5 extra GSP for 15 days and at the end gives you back the GSP you've used during those 15 days (excluding the extra 5)...I think. Only guildmaster can use this.
All these items require all eldrits plus a larger amount of unknown eldrits to craft them. They're all freely tradeable.
There's also small stuff like guild message, which you see every time you log in or the message is changed, plus every member can add an introduction of themselves in guild info. You can also see in the guild tab where other guildies are.
Guilds can advertise themselves on billboards (section Gildenwerbung), which costs some money. Players can only apply to a guild through these advertisements, otherwise they have to be invited by guild members (rank of guildmaster or guild manager is probably required to invite, offline players cannot be invited).