The demo does use the latest Version (1.6) code, so anyone can try that out if they're interested in playing the latest Version.
PvK: The 1.6 patch does make some pretty major changes and additions to the game and game balance. The download page for Coliseum here details everything that changed.
Antonin: There are still a large amount of people who e-mail me about the game, so there are still a good amount of players, I assume.
Try out the demo, if you're curious.