After the new update, steam hasn't allowed me to update the game because it states unsupported file system. I have tried reinstalling the game and the same issue keeps occurring. The game was working fine before the update. Is anyone else having this issue? 

Graxer wrote:

Are you playing on Linux with Proton and storing your games on an NTFS formatted drive or partition (a common format for Windows to use)? I was having issues with many of my games because I was doing that.

I had a preexisting folder I used on windows and it wasn't until I also connected Linux to that folder and it next tried to update the games that everything broke due to the filesystem being unsupported.

Thank you for sharing your experience. I've just checked and I am not using those. This is the only game that is having this issue. I've tried reinstalling the game onto a hard drive and there was no difference. I've contacted steam and yet to hear anything.