Macworld Apple introduced the APFS (Apple Filing System) file system protocol in macOS Sierra. It’s now the required format for macOS, but it took a while to transition from the former implementation of the HFS+ (Hierarchical File System Plus) format. Even during the transition, Apple kept the legacy standard HFS+ viable for backward compatibility. (It’s called “Mac OS Extended format (Journaled)” in Disk Utility.) Macs running versions of macOS as recent as Sonoma can still read HFS+ formatted volumes, even if you can’t boot a Mac from an HFS+ volume starting with macOS 10.14 Mojave. Apple al…