I just checked in at CCC's website, and I found this apparent update of the statement you've already posted:
The current beta of CCC 4 already works with APFS insofar as CCC can copy files to and from that filesystem. The current beta can also make bootable backups from an APFS startup disk to an HFS+ formatted destination volume – we've already tested that, and in the little bit of testing that we've done so far, that works great. The current feature set of CCC 4 will be qualified against High Sierra – creating bootable HFS+-based backups and working with CoreStorage encrypted backups will be qualified and functional (barring any OS bugs) and we aim to complete that by the time Apple ships High Sierra in the Fall.
Creating a bootable APFS volume, however, is brand-new territory. The semantics of starting a Mac from an APFS volume are completely different from those of an HFS+ volume. We have established a procedure to create an APFS startup volume, though, and we've even created a proof-of-concept bootable APFS clone. What lies ahead is a massive amount of engineering work to build support for these new procedures into CCC. APFS encryption is also handled quite differently from CoreStorage encryption, so we have a lot of work to do in regard to building in support for automatically unlocking and mounting APFS encrypted backup volumes. We're aiming to offer new functionality for creating APFS bootable (and optionally encrypted) backups by the time Apple ships macOS High Sierra in the Fall.
It seems to allay Harv's fears...to a degree, anyhow, but your informed opinion will be appreciated.
Hmmm... Your original CCC quote said "
Use an HFS+ destination for now if you require a bootable backup", so were Harv's fears unfounded in the first place?
