The social media company merged the direct messaging programs of the two sites in September 2020, part of a larger plan to merge the Messenger, Instagram, and WhatsApp chat programs and further lock people into the company’s ecosphere.

Starting in mid-December, however, that cross-app communication will no longer be available, the company announced in an updated Instagram help center posting. In real-world terms, that means Instagram and Facebook users won’t be able to start new conversations or calls with each other via the Messenger apps—and any existing cross-platform chats will become read-only, preventing users from sending or receiving additional messages.

Facebook users also will no longer be able to view the active status of Instagram users and vice versa.

The change in status for the two messenger apps comes as Meta is facing threats by the European Commission to regulate the Messenger service as a “core platform service” under its Digital Markets Act. That would force Meta to make Messenger nonoperable with other messaging services.

Facebook is fighting that, saying Messenger is a core part of the Facebook app and not a standalone feature (despite the fact that the Messenger app is separate from Facebook).

Earlier this year, Meta also shut down its Messenger Lite app, a stripped-down version of Messenger for Android devices. (That app had reportedly been downloaded 760 million times globally.) The company also dropped SMS support for Messenger.

The company also increased parental control for teens on the platform this summer, letting parents check their teenagers’ privacy and safety settings in Messenger, view their contact lists and get updates when someone is added or deleted, and see who’s messaging them.