I often use older versions of ardour to compare things when troubleshooting.
There was a change in the ardour config file added, perhaps 9.8, and elder versions of 9* don’t load anymore once that newer version has updated the config file.
I then have to move the “newer” config to a backup-place, rm it, then start the older Ardour version, then do the same to go back to my usual config file.
It usually is a “let’s quickly have a look”, and it is not that quickly anymore.
Not a biggie, sure, but i can be confused, and despite having a backup i would prefer to do something like:
/opt/Ardour-9.5.0/bin/ardour9 -c ~/.config/ardour9_old
Or any other comfortable “solution”, not asking if the give is possible, just what comes to my mind. This is not to create new projects,to do work, it really is always a “let’s quickly have a look if i see the same behaviour there”.