Hi,
I upgraded to 9.22, and tried to save in lbrn format so i can change back to 9.20, but even if i chose lbrn, LightBurn kept saving it or at least naming the file with lbrn2 extension.
I ended up renaming it to lbrn, loading it to 9.22, and then saving it back with ‘save’.
Then i could open it in 9.20
using Xubuntu 20.04