Just installed Build 41.56 on Ubuntu 20.04; I was previously running Build 40 fine, new version fails to start with the following issue:

Running Project Zomboid
couldn't determine 32/64 bit of java

Also, support chat gets to a stage of "Please choose operating system" then shows a blank list and won't proceed.

Hello MrScuffles

You need to remove the folders 'jre' and 'jre64' in game/projectzomboid/ and then reinstall the game, or better install the 41.65 version over it

I had the same problem and solved it that way