I want to update my iOS to 15.1
How to update my iOS to 15.1
iPhone 6s, iOS 13
what's stopping you?
if your details are correct and you are still running iOS 13, you may want to consider using a computer to do the update
have you read thru this support article for updating?
Update your iPhone, iPad, or iPod touch - Apple Support
need more storage for update?
If you need more space for an update on your iPhone, iPad, or iPod touch - Apple Support
issues?
Updating iOS: common issues and solutions - Apple Community
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