iPhone se unable to activate an update is required to activate your iphone

Hey there cherCait17,

Thanks for reaching out to the Apple Support Communities. We understand you're getting an error showing that an update is required to activate your iPhone, and we'd be happy to provide you with the best steps.

For help with this particular issue, we'd recommend following the steps listed in the following resource under the "What to do next" section: If you see an Update Failed or Apple Pay Not Available alert after iOS update or restart - Apple Support

If still having issues after those steps, then it's possible that the issue you're seeing may be hardware related, and the next best option would be to have your iPhone inspected further in person. Check out this next link for help with finding nearby service locations in your area: Find Locations - Apple

We hope this is able to help.

Take care.