Following the release of iOS 13.4 last week, Apple has stopped signing iOS 13.3.1. This means it is no longer possible to downgrade back to iOS 13.3.1 from iOS 13.4 on your iPhone.
While iOS 13.4 brings a number of new features and enhancements, it is currently not possible to jailbreak it. Many people tend to downgrade back to an older release of iOS so that they can jailbreak it. While checkra1n supports jailbreaking iOS 13.3.1, it only supports iPhone X and older devices. As for Unc0ver, it supports iPhone XS and iPhone 11, but it is limited to jailbreaking iOS 13 – iOS 13.3. The checkra1n team should update their tool soon with iOS 13.4 support as it relies on a bootrom exploit that works irrespective of the iOS version.
If you were looking to downgrade your iPhone or iPad to iOS 13.3.1 for any reason whatsoever and had not already done so, there’s not much you can do now. Your iPhone is now stuck running iOS 13.4.
Were you considering downgrading your iPhone to iOS 13.3.1 from iOS 13.4? If so, why? Drop a comment and let us know!