Hacker News Reader

It replaced (as of iOS 10.3) HFS+ on the mobile devices as well, didn't it?

Almost correct. 32-bit devices that received iOS 10.3 did not receive APFS. It was exclusively delivered to 64-bit devices.

It's also worth noting that the first 64-bit iPhone/iPad were released in 2013, so they've been around for a while.

The iPhone 5c will have the shortest support window from its release, at 4 years.

Yes.