Facebook seems to be acting on its plan to unify messaging across its apps, however slowly. People at The Verge (and likely elsewhere) have received notice through Instagram’s Android and iOS apps that they’ll have the ability to “chat with friends who use Facebook” — that is, Messenger. The signature paper airplane icon for DMs has been replaced with Messenger’s logo. You can’t actually message Facebook friends yet, however, suggesting the announcement might have come early.
The update also brings a “more colorful” appearance to chats, and the option of replying to messages by swiping on them.