The FS2NetD server will be offline for approximately one hour starting around 4:00am GMT. The downtime will affect the 3.6.9 daemons, the 3.6.10 deamons, as well as the lobby chat server.
All of the software will be upgraded to include new fixes and various improvements to improve maintenance and facilitate upcoming feature upgrades. The game daemons should be back online within minutes, but the lobby chat server will be going on and off-line randomly during the one hour period, so it's advisable to just wait the full hour before trying to play games again.
I'll try and have it all back up and going as quickly as possible and will update this post once everything is safe again.