Apple has stopped signing iOS 13.1.2 and iOS 13.1.3 today. This comes after last week’s release of iOS 13.2, which included additional bug fixes, performance improvements, and new features.
Apple generally stops signing older releases of iOS within a few weeks of releasing an update to the public. iOS 13.2 was released last week, while iOS 13.1.3 was released two weeks before that.
When Apple stops signing an iOS build, it means users are no longer able to downgrade to that version via iTunes. Reverting to older iOS builds is common for those in the jailbreak community and can sometimes also be useful for users who experience significant bugs after updating to the latest version of iOS.
Furthermore, an exploit called “checkm8” has gained traction, offering a jailbreak for older-model iPhones, including the iPhone X.
Yesterday, Apple released the first developer beta of iOS 13.3. This will likely be the next public release of iOS, with fixes for RAM management, Screen Time communication limits, and more.
Source: 9to5mac