According to mashable, facebook soon disable chat feature from their main mobile facebook app. Facebook has also confirmed that the ‘Chat feature will be removed from iPhone and Android App. While the European users have been receiving notice about this change.
Soon the Facebook mobile app is updated, and it will delete the chat feature. The users, who want to interact with their Facebook friends that they must have to install Facebook Messenger on their mobiles.
The Company will send alerts and notices to users Before this change.