Apple releases iOS 13.5.1, patching out the Unc0ver jailbreak - The Verge

But as noted by Twitter account Apple Software Updates, the update is meant to patch out the kernel vulnerability used by the recent Unc0ver jailbreak.

Apple’s support page lays things out more clearly — the update was designed to prevent an application from being able to “execute arbitrary code with kernel privileges.” In other words, iOS 13.5.1 is designed to block jailbreaking.

The Unc0ver jailbreak was particularly notable in the iOS jailbreaking community because it was available on the then-current iOS 13.5, allowing users of the latest Apple devices to install new software features outside of Apple’s gated App Store