After last week iOS 13.1.2 arrived to all users in the form of an update, Apple has stopped signing all its old versions. This means that you can no longer download to an earlier version of the operating system, so any automatic or manual update must be equal to or greater than iOS 13.1.2 on iOS devices.
Last Friday was when Apple stopped signing iOS versions 12.4.1, iOS 13.0 and iOS 13.1.1 for compatible devices. However, it continues signing and allowing users to update iOS 13.1. This jump is due to the fact that iOS 13.1.2 has probably been an urgent update to correct some important bug in iOS 13.1.1, so the company did not want users to be able to continue updating to iOS 13.1.1 and jump directly to iOS 13.1.2
Now however everything has cleared up a bit more: iOS 13.1.2 or nothing. The only available version to which the iPhone can be updated is iOS 13.1.2, the latest version that Apple has published. The impossibility of doing downgrade to an earlier version it is a method and strategy to promote that there is no fragmentation of the system and therefore improve the security of all iOS devices.
While iOS 13.1.2 is the most recent public version of the mobile operating system, developers are already testing iOS 13.2 in beta. The main novelty that we will find in iOS 13.2 has to do with the camera of the iPhone 11 and the Deep Fusion mode.
Goes | MacRumors
Apple stops signing iOS 13.1 now that iOS 13.1.2 has arrived