With the release of macOS Sierra last year, Apple debuted a new filesystem dubbed APFS (Apple File System). The new file format is meant for solid storage drives, with focus on encryption and data integrity.
APFS support in macOS Sierra is very limited, though, with Apple expected to make it the default file format in the next version of the OS. However, if the iOS 10.3 beta release is anything to go by, Apple is seemingly looking to jump on the APFS bandwagon earlier than presumed.
Apple notes that with the iOS 10.3 release, the file system of iOS devices will be upgraded to APFS. This includes the iPhone, iPad, Apple Watch, and Apple TV. Impressively, the file system conversion will take preserve your existing data, though, Apple does recommend one to create a backup of their device before updating.
When you update to iOS 10.3, your iOS device will update its file system to Apple File System (APFS). This conversion preserves existing data on your device. However, as with any software update, it is recommended that you create a backup of your device before updating.
It will be interesting to see if the switch to APFS will bring any noticeable improvements in performance or not. It is also interesting to see Apple not wait until the release of iOS 11 to make the switch to APFS. And despite Apple first making APFS official with the release of macOS Sierra last year, the release note of macOS Sierra 10.12.4 does not indicate that the update will convert the HDDs file system to APFS.[Via Ars Technica]