I don't think they mean "devices". Time Machine backups are complex. They have millions of hard linked files and folders, and are also protected by the Time Machine kext.
We handle that up to 10.13.x. However, Apple may change the way TM backups are "protected" in 10.14 and later, and at that point we may not be able to copy them.
Note, though: Apple now allows you to have multiple Time Machine destination volumes, and disks are cheap. In addition, Time Machine is not intended to be an 'archive'. I would generally suggest two Time Machine destination drives for serious use (effectively backing each other up), and then starting a new one if you need more space.
__________________
--Dave Nanian
|