Patch 1.05.6 is currently on the test server, and it will be staying there for about another 2 weeks before it makes its way to the live servers, barring any unforseen testing mishaps, of course. That's the patch that has the new Iron Tower instance and the veteran rewards system.
Once 1.05.6 is out on the live servers, patch 1.06 will be pushed onto the test server. Patch 1.06 is the big one, featuring new tier three dungeons, the House of Crom "social dungeon" where multiple teams of players will work to overcome unknown obstacles, guild renown, and tower PvP. 1.06 will be added slowly to the patch server, however, focusing on the bigger updates like guild renown and tier three dungeons before moving on to the other features of the patch.