'My iphone 11 not installing the software update 17.1

If your update is downloaded but will not install, please remove the update file and download the update again. See this on how to to that

Go to Settings > General > [Device name] Storage.

Find the update in the list of apps.

Tap the update, then tap Delete Update.

Go to Settings > General > Software Update and download the latest update.

Please read through the user tip below for possible causes and cures.

Updating iOS: common issues and solutions - Apple Community

I will assume you are referring to iOS 17.4.1.

What happens when you attempt to update?

Any error messages?

What is the existing version?