Adding to what Chris said, we have made some significant enhancements to versioning starting from PowerBuilder 2019 R3.
1. You can have multiple runtime versions co-exist on a machine, no matter it is minor version (e.g. revision) or bug fix (e.g. MR).
2. You no longer need to log in and out of multiple versions of the PowerBuilder IDE. In other words, you can work simultaneously in multiple IDEs.
3. Although IDE versioning is same as before in that only major versions can co-exist on a machine, but now one single IDE can compile for multiple runtimes. So perhaps there isn't even the need to have multiple versions of the IDE anymore.
But just keep in mind that the above changes applies to PowerBuilder 2019 R3 and newer only. PowerBuilder 2019 R2 and older will still have same limitations as before.
In case you are interested, there was a good Webinar about the enhancements in 2019 R3 and the recording is available.