How to upgrade a drive with High Sierra and APFS

The new Apple File System (APFS) that replaces the long-running HFS+ in macOS caused a lot of concern and confusion, because it seemed like a massive change, but the effects aren’t noticeable to end users, except in improving the speed of SSD-only Macs. (Apple doesn’t upgrade hard drives to APFS, and hasn’t yet released a Fusion APFS update for its mixed SSD/hard drive systems.)APFS restructures how files are stored in a disk partition, but it doesn’t change how programs