It was a massive change, but one they prepared for by having the same migration happen on laptops/desktops
The old filesystem was HFS+, released in 1998 and APFS was released in 2017.
APFS added encryption, data integrity checksums, copy on write, snapshots, logical volume support. The migration wasn't just a "search and replace the name and ship it", but an intensive re-writing of the filesystem metadata during the migration.
The old filesystem was HFS+, released in 1998 and APFS was released in 2017.
APFS added encryption, data integrity checksums, copy on write, snapshots, logical volume support. The migration wasn't just a "search and replace the name and ship it", but an intensive re-writing of the filesystem metadata during the migration.
https://en.wikipedia.org/wiki/HFS_Plus
https://en.wikipedia.org/wiki/Apple_File_System