My current IOS version is 13.7 , I want to upgrade it to IOS 14 not IOS 15 (I am using iPhone 8 )

liamwazza's solution is not open to you.. Resetting even to "factory settings" does not affect the installed ios version

You cannot go backwards from 13 without jailbreaking which is security nightmare.

Your only choice to get the latest serious security updates is to iOS15.

iOS 13 had some serious security holes.

Had you been on 14.5 or 14.6 you could have stayed on 14.8 and still receive security updates but that opportunity is not there for you.

Hello,

You can only update to the current version of iOS. Note: iOS 15 works just fine on an iPhone 8. See this:

Update your iPhone, iPad, or iPod touch

Updating iOS: common issues and solutions

Good luck.

Once settled down for a day or two, yes. A lot of the improvements are not available to run on older phones.

Naturally make sure all apps are updated, NextDoor being a big burner, and remove any VPN as many are not compatible.

None of that is correct unfortunately.

You can revery back to a previous version. First go to settings > Icloud >backup > backup now

then go to settings > general > reset > reset settings

note that this will put it to the original ios from your phone so if that was ios 12 then it will reset to that but the only update will be ios 15 so you’d have to stay on 12

my iPhones 6S and 7 both run just fine.

You are welcome.