The default application to open a specific type of file is set at the OS level. With Windows, it should be from Parameters - I must say I haven’t got there for a while.
Most importantly (even though not answering your question): backup your files!
The biggest danger will be that when you are saving an older file in a newer version (by mistake or on purpose), that you will not be able any longer to open it in the older version. It is probably best to not only have multiple versions of Xojo installed, but having a versioned backup hierarchy of your most precious files. Especially with binary files there is little chance you will be able to get your work back in the worst case.
When working with multiple Xojo versions I make sure to start only one version of Xojo. If I start and use the wrong version I revert in Cornerstone (SVN).
Hi , can’t you setup and work on docker containers ? Then you have always a defined environment.
Or setup multiple VMS. In old times I was using different hard disks… .
Another option is a tool like gclient ( depot tools from chromium project). Everything is defined in a deps file, which is also checked in. And the starting point is always a glient sync … .
HTH
BR Rainer
I figured out that if I install the latest, then reinstall 2018r4 (my production choice), 2018r4 is the default in the event I just open a project without thinking about it. This works for me.
I use Git, and my code sits on 3 machines, so I feel I have a backup. I also make a copy of my Git folder periodically.