10/10 for doing this.
I have been using the nightly builds from group_kicad-kicad. At nickoe’s suggestion, I just switched to aimylios:kicad-nightly-test. On loading my schematic, KiCad tells me that it must save it in a new format which is not backwards compatible. I see new .kicad_sch files instead of my old .sch files.
I think the need to go with the new format should be listed in the Known Limitations. It certainly means the stable release can’t be used side-by-side with the new nightly.