Portrait orientation lock on/off iPhone 7

If the forced restart procedure (suggested in my previous post) didn't work for you, something could have gone wrong with your update.

The next basic troubleshooting step to perform is to make a full backup of that device, then restore it to factory settings and, in the end, set it up as new: this installs a fresh copy of latest iOS on your device. See this support guide:

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

When done, test your device for a while without restoring data from backup. If the accelerometer works fine, you can exclude a hardware failure.

Then restore data from your previously made backup:

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Regards

Giulio

That problem is not related to iOS update (since I've never read here about that issue). I have many friends who use iPhone 7, and none of them suffered this malfunction after updating the operating system.

Instead of giving bad advice, why don't you try to perform the basic steps to restore the accelerometer functionality? Start with: Force restart iPhone - Apple Support

Regards

Giulio