This is a leaked version of Tribes v1.40. That means there are going to be bugs, and all scripts will have to be rewritten.
It is backwards compatible and can play on servers that use 1.11 and down.
New features:
Higher resoultion texture support with the .png format
Radar hud
You can now see the boundaries if you enable it in the options
Wide screen is supported
Lots of other stuff
I personally fixed the map files so that they don't throw errors in the logs any more. I also have it set to auto-refresh the server listing. The key-binds have also been changed back to those of a normal Tribes install.
You can host dedicated and non-dedicated servers with this, but you can't host a mod.
Info about the leak: http://www.tribalwar.com/forums/showthread.php?t=606831
Support info: http://www.annihilation.info/forum/viewtopic.php?f=1&t=8139