Time Machine Catalina issues
On my MacBook was preinstalled Mojave 10.14.5, I did a backup on WD external hard drive (file system MacOS journaled) and then upgraded to Catalina 10.15.5. Now my Time Machine just won't do any backup: first attempt ended with a stop, the second hadn't even started. Should I change my file system to APFS and what to do with Mojave backup if I may decide to downgrade back to 10.14.5?
MacBook Air 13″, macOS 10.15