The release notes say it doesn't work.
Why exactly do you want to convert your backup to APFS?Release notes for beta 8 I haven't seen, do you have a link?
Why exactly do you want to convert your backup to APFS?
All the power to you bro. Not completely following you, but best of luck messing around.Just for testing purposes I guess... Or just for fun to see if it works. In any case, it would probable cause an extra high, with your mac already High on Sierra, when you make a copy of your whole TM back-up BEFORE you progress. If you have a problem, it maybe unproblematic when you have a back-up of the TM back-up. Alternately you could first try to convert the copy..... see how that goes and then.... wait a while to see if it is stable during further back-ups.
Why exactly do you want to convert your backup to APFS?
All the power to you bro. Not completely following you, but best of luck messing around.
Time Machine still only supports Mac OS Extended (Journaled).Hi !
I'd like to know is it's still not recommended in 2019 to format a TimeMachine volume in APFS. Because theorically, it should be ok. I've got a Mac Pro 5.1 with 10.13.6 and a MacBook Pro with 10.14.6
Time Machine still only supports Mac OS Extended (Journaled).
https://support.apple.com/en-us/HT208496#which
From the linked Apple page:
"Are you preparing a Time Machine backup disk or bootable installer?
Choose Mac OS Extended (Journaled) for any disk that you plan to use with Time Machine or as a bootable installer."