The DMA requires that Meta “must be ready to enable interoperability with other services within three months of receiving a request,” but according to the blog post, actually turning it on for public use could take longer than that. The requirements also only mandate support for one-on-one chats and sharing files like images, videos, or voice messages “in year one” of the new regulation before they expand over time to include group chats and calls.

Meta says third-party providers will have to sign an agreement to interoperate with Messenger and WhatsApp before the company will work with them to implement it. The company asks that other providers use WhatsApp’s Signal protocol for encryption but says it will accept others if it finds they meet the same security standards.

The company promises that E2EE chats will be secure in transit, whether the other provider uses Signal or not. However, Meta won’t guarantee that the apps on the receiving end of WhatsApp and Messenger users’ chats won’t do anything unsavory.