If you encounter an error while trying to update your iPhone, please refer to Apple’s support page here: https://support.apple.com/en-us/HT204204
This update also includes the ability to fully disable location tracking on the iPhone. Back in December, it was revealed certain iPhone models would continue to track your location even if ‘Locations Services’ were disabled. This was due to the way the ‘U1 Ultra Wideband chip’ worked on these models.
As well as disabling locations services you can now disable the U1 Ultra Wideband chip by going to Settings > Privacy > Location Services and tap the ‘Networking & Wireless’ toggle to OFF.
Here’s a full list of changes in iOS 13.3.1:
What to know more about the main features in iOS 13? Check out our iOS 13 Features and Changes page.