I updated my iPhone7 to iOS 15.3.1 but it can’t install

I notice you have automatic updates on. Do you get an error overnight when iPhone attempts to install the update as well?

Try restarting your iPhone and try again, first.

If that doesn't solve the issue, try re-downloading the update. Go to Settings > General > iPhone Storage. Then, scroll down until you see the update. Tap the update and delete it. You can then download the update again and try installing it again.

If the update still won't install, contact Apple Support.

Hey there,

See>>>If your iPhone, iPad or iPod touch won’t update - Apple Support

Greetings!