Most importantly, this updates the shared bits of netcode - for example, if your connection is a little spotty (packet loss), the game should now hold up much better. There are also other minor improvements and fixes (e.g. timing out if a person dropped out of lobby).
On other notes:
- Fixed a crash with arena buy-confirm panel when using Japanese locale
- You can now open inventory during arena mode. Mostly for staring at your stats, but do what you may.