Why can’t I download new apps

iPhone 5s, iOS 11

You can update your iPhone to iOS 12.5.7 is the latest iOS security update for iPhone 5s.

See -> iPhone models compatible with iOS 12

Supported iPhone models – Apple Support (UK)

Go to Settings -> General -> Software Update -> Download and Install (if you haven't already done that).

iPhone 5s can’t be update to a higher iOS (13 and later). 

If you have an outdated iPhone that cannot be updated to iOS 13 or later, many apps will not be able to download.

Outdated iPhone no longer meets the requirements for many apps.

Most apps require iOS 13.4 or later.                                

Considering a newer type of iPhone?

Read this before you buy a newer type iPhone.