To quickly check this, go to and select your device and desired software version to see if the iOS is still signed. If the software version is no longer signed, Apple has stopped supporting the iOS version and you cannot downgrade.
This is because there is no way to downgrade your watchOS, and this may cause incompatibilities. While you can still use an earlier backup, you will still be losing some data. This is because a later version backup cannot be used after you downgrade to an earlier software version. Because of this process, there are a few important points you need to consider before making the decision to uninstall the latest iOS: To reinstall an iOS update, you'll need to download the previous software version on your computer, restore your iPhone to factory settings, load the downloaded software on your iPhone, then restore your data from a previous backup.
