The update has been a frustrating one for players because it would often crash and then reset the game world, so these two issues we're combining to make a number of players lose their progress. Iron Gate has been working to address the matter, but had to work to identify the issues and then thoroughly test them to be sure that they could be addressed correctly.
The team promised a patch but, in the meantime, had made some other changes to the save process and warned the community. Now that promised patch is live, and it not only addresses the crash and reset issues, but makes some changes to help safeguard data.
Several of the changes are intended to keep data safer. There is now a new auto backup system that will keep two customizable backups by default. One of these will be a two-hour backup, and the other will be 12 hours. The game will also save after you sleep, or at 30 minute intervals, with this timer resetting when you use the manual save console command. Using that console save command also will now save the character file.
If your world gets corrupted, world save will be disabled end the game will return to the main menu and shut down and he dedicated servers running corrupted worlds. Steam Cloud saves have also been changed to prevent a crash that was happening during saves that could actually corrupt the world. There are also some changes to naming, like being unable to create a world with the same name as another one when you have Steam Cloud save enabled.
You can read the full patch notes here, and the fixes address the issue from several different sides, including more backups in case issues do happen.