Unable to restart the phone because it shows that to restore your iphone with iOS 15.3.1 you need to instal the latest version of iTunes

Hello saiva194,

Thanks for using Apple Support Communities! We see you're having an issue with restoring your iPhone because of an iTunes error message, and we'd like to help.

You didn't mention if you were using Windows, and which version, or if you have Mac with macOS Mojave or earlier.

For a Windows PC, you'll need Windows 7 or later:

For Windows 7: iTunes 12.10.11 for Windows (Windows 32 bit)

For later Windows versions:

Download and use iTunes for Windows

For Mac:

Update to the latest version of iTunes

Take care!