Apple has released iOS 26.4.2, a seemingly minor security update for iPhone that turns out to patch a serious security vulnerability that allowed the FBI to read sensitive messages from the Signal messaging app, even after the app had been deleted. In early April,  404 Media reported  that the federal organization had extracted the messages from a defendant's phone because the system still contained copies of the notifications that were generated when the texts were sent. Although Apple doesn't specifically call out the FBI incident, the description in the company's  security note  (which also applies to iPadOS 26.4.2 for iPad models) matches the issue. "Notifications marked for deletion could be unexpectedly retained on the device," the note reads. The update fixes a logging issue "with improved data redaction." To bring your iPhone or iPad up to date, go to  Settings  and tap  General .…