On Jun 25, 2020, at 18:06, Michael wrote: > That's 10.15, that requires the root drive reformatting, with no compatible > driver for older systems, right? > > (Whether or not it's a better file system isn't the issue. 100% breaking > compatibility with everything older is a bad move.)
Huh? On my 2012 MacBook Pro that I'm using for testing at the moment, I had no problem installing Catalina on an APFS volume, while also having Mojave and High Sierra installed on separate APFS volumes on the same partition, and having Lion and Sierra installed on separate HFS+ partitions, all on the internal disk.
