Tech giant Apple has stopped signing iOS 15.1, which means that users who updated their devices to iOS 15.1.1 or iOS 15.2 beta can no longer downgrade to iOS 15.1.
According to 9To5Mac, this comes a month after the company stopped signing the iOS 15.0.2 firmware.
iOS 15.1 was released to all users in late October with some new features, including the Covid-19 vaccination certificate in the Wallet app, SharePlay on FaceTime, ProRes for iPhone 13 Pro users and more.
The update also brought an option to manually disable Macro mode on the iPhone 13 Pro and iPhone 13 Pro Max, the report said.
A few weeks later, Apple released iOS 15.1.1 to fix some bugs that were affecting iPhone 13 users.
According to the company, previous versions of iOS 15 have a bug that causes phone calls to drop unexpectedly.
Reverting to older iOS builds is often used by those who jailbreak their iPhones, the report said.
Restoring an iPhone or iPad to a previous version of iOS can also sometimes be helpful for users who experience significant bugs after upgrading to the latest version of iOS, it added.