A Pentagon-wide advisory that went out one week ago warned against using Signal, the messaging app, even for unclassified information.

The Pentagon warned against using Signal in a memo just last week, according to NPR. It cited threats from Russian hackers. The memo was delivered department-wide days before The Atlantic published a bombshell revelation that its editor-in-chief Jeffrey Goldberg had been erroneously added to a Signal group chat that involved detailed discussions of planned strikes on Houthi rebels in Yemen,