Jeroen (vts on the forums) has worked on fixing things, perhaps most notably making selecting units a lot easier (a more technical explanation: he's worked on making the bounding boxes correspond better to the actual models). He's also worked on adding rally point marker lines. In other words: the rally point you place to tell newly created (and ungarrisoned) units to go to a certain spot on the map can be a bit hard to find at times, but with this feature you get a line on the ground showing you the way to it. And also roughly the way the units will walk to get to it. It's probably easier to see how useful it can be from a screenshot though, so below you have one:
Rally point marker line, the line going from the building to the rally point.
Yves (Yves on the forums) has mostly been working on upgrading to premake4 and other compile related fixes (a less technical explanation: he's made it easier for people to build the game - the process of turning the code into an actual game that can then be played).
Jonathan (quantumstate on the forums) has been (and still is) the leading force behind qbot, one of the AIs for 0 A.D.
A video showing a match against one of the latest versions of qbot.
Second, we've gotten a new artist on board: Enrique (Enrique on the forums), who has already created some marvelous Roman buildings which will help enhance the game world.
New Roman temple (to the right, to the left is the Hellenic temple for reference).