If you updated your iPhone to iOS 10.3 already you may have noticed that it’s running quicker than before. That may be due in part to the fact that the new update is reportedly freeing up loads of space up updated phones.

The new update offers a number of new features. But one of the more important aspects of iOS 10.3 is that it updates the files on your device from an old file system that Apple has been using for more than 30 years to a new system.

Read: How To Backup Your iPhone Before You Update To iOS 10.3

If you’re running your device on anything older than iOS 10.3, your files are in HFS+ or HFS formats, but if you’ve updated then your phone is running on APFS. The new file system, APFS, is designed with strong encryption and limited memory overhead meaning all your apps will take up less space and your data will be safer.

People who have already updated are reporting fairly large increases in available storage once the update is complete thanks to the change in file systems.

One user reported gaining 5GB back after updating.

Most users on Twitter were gaining at least a full GB.

Before you update your phone you should always back it up, but especially with this update because the transition from HFS+ to APFS may not go perfectly, so you want to be sure you have your files and data saved either on your computer or in the cloud.