I made this simple app to enable chat again in main Facebook app without installing Messenger.
Works between Android 2.3 and latest 5.0, on any device that supports Facebook app.
Disadvantages of Facebook+Messenger installed at same time: HUGE battery drain and RAM consumption, device may slow down etc. (especially low-end devices)
Advantages of Facebook Chat Enabler: It’s only an enabler and is never executed by the system, meaning no battery drain/RAM consumption/resource eating at all. (Facebook app itself drains battery)
Its name and package name are the same as Messenger app, so Play Store may notify “Update available”. BEWARE and don’t update!! Otherwise you’ll need to install again this app.
You don’t need to do anything else, just download and install. After installation, no icon is showed in menu and chat will magically work!
Confirmed working on following Facebook versions:
184.108.40.206.12 (latest Play Store version)
New updates in future may break this (and to use again Chat Enabler you’ll have to install last confirmed working version
OVERVIEW POST ON XDA
Facebook is the undisputed king of the social sites (with others such as Google + gaining popularity… and fast). Because of this status, they can pretty much do anything and everything they please with their platform, and users are to either take it or leave it. One of Facebook’s latest moves, which royally annoyed a lot of people, was that they killed off chat functionality in their Android app. As an alternative, Facebook released what we know today as Facebook Messenger, which as its name rightfully implies, takes the place of the aging Facebook app feature. This change came coupled with a lot of talk and conspiratorial theories which pointed at Facebook essentially snooping on your every move because of camera and microphone permissions (after all, it isn’t like those permissions are needed to attach pictures or send audio, right?). After a few official statements, all seems well in Facebook land. However, what about the fact that you now have yet another app (and not a tiny one) on your device? It is like the Facebook app had an offspring and decided to unload part of its functionality to it. For those who still miss having one app to do it all, XDA Senior Member AntaresOne has created a simple, yet effective solution.
Facebook Chat Re-Enabler basically does what its name implies. It re-enables the chat feature on the Facebook app. Removing such a feature should have resulted in a supposed drop in app size when the feature left the scene. However, it did not and the real reason behind it is because the Facebook team basically made it dormant as opposed to removing the code altogether. AntaresOne’s fix basically re-enables this functionality. The advantages of taking this route are that you now have about 17 MB more of storage at your disposal and you no longer have to worry about this thing draining your battery. This app runs once and voila! Chat is back in all of its glory.
The fix has been confirmed to work for versions 220.127.116.11.15 and 18.104.22.168.12, which happens to be the latest on the Playstore (as of the time of this article at least) and it is compatible with Android 2.3 all the way to the debuting Lollipop. Feedback for other versions of the app is highly appreciated. So, if you have any, please drop by and leave a few lines. You can find more information in the original Facebook Chat Enabler thread.
Thanks to AntaresOne (XDA)
Facebook Chat Re-enabler
Original Post XDA
Fahim Shaikh For Sharing Post and Download file
Farhan Imaan Publishing