Does Files Connect support macOS 10.13 High Sierra?

Yes, Acronis Files Connect (formerly Acronis Access Connect) is fully compatible with macOS 10.13 High Sierra, as well as earlier versions of Apple's macOS / OS X operating systems.

Does Acronis Files Connect work with HFS+ and APFS disks?

Yes, it works fine with either disk format.

What's the difference between AFP and APFS?

They're very different but easy to confuse because of the similarity of the names and abbreviations.

AFP stands for Apple Filing Protocol. It's a network file sharing protocol, similar to SMB. AFP is one of the ways that a Mac can connect to a Windows server running Acronis Files Connect.

APFS stands for Apple File System. It's a file system for local Mac disks, which Apple added as an option for SSDs in macOS 10.13 High Sierra. It's intended as a successor to the HFS+ file system that Apple's used since 1998.

Is there an AFP limitation with APFS?

Technically yes, but it's irrelevant to Acronis Files Connect (and most users in general).

The limitation is just that if a Mac users creates a personal file share from a local folder on a disk formatted with APFS, it will only be shared over SMB. For example, a Mac user sharing out the Music folder from a MacBook.

That has no impact on the Mac’s ability to connect to AFP file shares hosted on a Windows server running Acronis Files Connect -- which is designed to let Mac users search and connect to Windows servers or NAS devices. 

To be clear, Mac users can use AFP to connect to shares the same as they always have, regardless of the file system format used for local disks.