You Can No Longer Downgrade to iOS 13.6 or iPadOS 13.6
You Can No Longer Downgrade from iOS 13.6.1 to iOS 13.6 as Apple has Stopped Signing the Older Firmware
Released just a week ago, iOS 13.6.1 and iPadOS 13.6.1 are nothing more than bug fix updates. If you are looking for new features, you won’t find them here. And since this is a new update, which means it was only a matter of time Apple was going to stop signing iOS 13.6 and iPadOS 13.6, cutting off the process of downgrading to said firmware altogether. Today is that unlucky day and Apple is no longer signing iOS 13.6 and iPadOS 13.6.
Since you cannot jailbreak iOS 13.6 and iPadOS 13.6, therefore this news should not bother you one bit. In fact, I would suggest updating your devices to iOS 13.6.1 and iPadOS 13.6.1 to ensure smooth day to day functionality.
Please, do not attempt to downgrade your device to the older firmware. You will only be wasting your time if you do so. Once Apple stops signing any firmware, it means your chances of downgrading are long gone. If you are experiencing problems on the latest software update, then it is best to troubleshoot those issues using various methods, or by simply resetting things over and starting fresh with iOS 13.6.1 or iPadOS 13.6.1.
You can either perform a clean install of the firmware or just download it over the air, the choice is entirely yours.