Also: What is Signal? 7 features that make it a go-to app for private, secure messaging

As is sometimes the case with Apple update notes, the explanation raises more questions than it answers. However, the reason for the update lies in the Signal app itself and in how the feds were able to skirt its security.

In a federal trial that concluded last month, several individuals were charged with and found guilty of setting off fireworks and vandalizing property at an ICE detention facility. One of the defendants, Lynette Sharp, had used Signal on her iPhone and later deleted the app, 404 Media (subscription required) reported earlier this month, citing people present at the trial.

During the trial, however, an FBI agent testified that the agency was able to access Sharp's incoming Signal messages because copies of their content had been saved on her phone's push notification database.