I am having the same issue, running on Linux (Mint 19.3).
I checked the logs and I got a lot of occurrences of this error
/lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.29' not found (required by /home/xxx/.local/share/Steam/steamapps/common/ProjectZomboid/projectzomboid/libjassimp64.so) at FutureTask.report line:122..
my version of glibc is 2.27-3ubuntu1, and afaik, it's not safe to upgrade glibc, since it might break already compiled programs in my system.
Is there something I can do on my end to fix the issue?
Looking forward to play the update! a lot of new cool features!
Thanks!