How to downgrade from iOS 26.1 to a previous version?

ita826 wrote:

I am absolutely fed up with latest IOS. Here in the UK it’s completely slowed down performance on both phone and watch. Watch is literally useless without high speed WiFi. Navigation on the iPhone is beyond slow. How to demote from 26.1 to the previous version?

[Re-Titled by Moderator]

Original Title: Demote iOS

Downgrading is not, nor has it ever been supported, so you can't go back.

What you haven't told us is anything about the iPhone you own.

• What model - Settings > General > About > Model
• What is the Battery Health -Settings > Battery > Battery Health
• How much memory is available - Settings > General > iPhone Storage
• After the update did you Force Restart (I do after every iOS update) --> Force restart iPhone - Apple Support