Following the release of iOS 13.5 last week, Apple has stopped signing iOS 13.4.1 and iPadOS 13.4.1. This means it is no longer possible to downgrade your iPhone or iPad running iOS 13.5 to it until and unless you have the SHSH blobs backed up.
Most iPhone owners usually tend to downgrade to an older version of iOS to jailbreak it. However, this time around, there’s an iOS 13.5 jailbreak available for all compatible iPhones and iPads meaning there’s no reason for anyone to downgrade back to iOS 13.4.1. Even the checkm8-based Checkra1n jailbreak has already been updated with iOS 13.5 support for iPhone X and older devices.
iOS 13.5 also brings a number of changes and enhancements for a world with coronavirus so it is a pretty important usability update. Among other things, this release of iOS supports the Exposure Notifications API that could be used by the health bodies of various countries for their contact tracing app. If your iPhone or iPad is still running iOS 13.4.1, you should upgrade to iOS 1.5 for all the changes it brings to the table.
In case you have a jailbroken iPhone, you should first update it to iOS 13.5 and then jailbreak it again. Apple will likely release iOS 13.5.1 sooner than later to fix the 0-day exploit which is used by Unc0ver for this jailbreak so make sure to turn off auto-update on your iPhone.