After several months of testing and improving, we have released multiplayer to everyone - no need to opt in to the beta. Everything you can do in a single player sandbox game can now be done in Multiplayer. We've worked hard to reduce the bandwidth requirements and to increase the reliability - please let us know if you keep having problems!
Here's our video demonstrating the finished sandbox multiplayer:
https://www.youtube.com/watch?v=nNaJYeB85S8
Worth mentioning that these game modes are not supported in multiplayer yet: Escape Mode, Warded Mode, and any prisons that require Mods.
Thanks to everyone who supported us over the years - have a great xmas, and we will see you all in the new year!