Version mismatch

[BritvaWEED]

Hello everyone. My friend and I are trying to play co-op and we've been previously playing couple of times, but for some reason we're getting the error message "Version mismatch".

https://ibb.co/sG9ZyjN

We're both on a same version v0.3.4f8 but I'm not getting output for his version. We've tried to restart game, restart Steam and to verify game files but without a success.

Has anyone else experienced this issue?

Thanks