How to downgrade iPhone 11 from iOS 26.3

Hi, in theory and practice a downgrade a possible and the risk are extreme. You could brick your device. End of story, you’re responsible for any downgrade attempts.

Apple Support Communities doesn’t offer advice or instructions on the possibility of downgrading a device. This would be a violation of the terms and conditions we all agreed to when we joined Apple Support Communities.

If this is something you want or need to peruse, there are multiple posts on social media such as Facebook, Reddit, YouTube and many more on non-authorized methods. Please be aware that any attempted downgrade may void any warranty including AppleCare.

There is no method to downgrade.

Previously, you had to manually "tell" the iPhone to update because you had automatic updates turned off. In other words, updates did not occur automatically.

But, you may not have been aware that Apple made some changes and updating to a newer IOS version changed the setting for future updates to occur "automatically" even though you previously had the iPhone set to not update automatically.

So, when an update became available, your phone updated automatically at the time.

Check the settings on your phone if you do not want the next update to occur automatically.

It could....and likely did....update when you manually ran the update at the time.

At that time, you had to manually instruct the iPhone to update.

But, you may not have been aware that doing this changed the setting for future updates to occur "automatically". So, when the update became available, your phone updated automatically at the time.

What version of software were you using before iOS 26.3 was installed?