Facebook is now gradually rolling out support for increased sizes for group instant messaging, as well as group audio and video calls.
Starting today, users will be able to participate in live text chats of up to 250 people from a Facebook group. In addition, users can also join in voice and video calls that support up to 50 people simultaneously.
In order to avoid spamming users with chat and call notifications, each user will only be notified the first time they are invited to a chat unless they voluntarily choose otherwise. Support for these larger groups also allows users to only be notified of direct "@" mentions to them specifically.
According to Josh Constine at TechCrunch, this feature is being implemented at a time when there are 1.4 billion monthly active users in tens of millions of Facebook groups. These increased group sizes further differentiate Facebook Messenger chats from WhatsApp Messenger's group chats and Instagram's group direct messages, also owned and operated by Facebook.