[Android Apps and Games] jineshpatel30:
FAQs

1. What if my phone came with Facebook as a system app, and I can't uninstall it?

This is unfortunate, because trying to directly install Facebook LC on such a phone will result in a package conflict. The phone will not accept the modded FB app because it has the same package name as the System FB app, and they are not signed by the same key. One possible solution is to use something like App Clone or APK Editor (or perhaps something that's free) to change the APK name of Facebook LC from the default name ("com.facebook.katana") to something unique, to avoid the package conflict with the System FB version. However, this may lead to residual problems with the interactions between FB and Messenger. Even though you can probably re-name and re-sign both Facebook and Messenger, the problem is that even through their names have been changed, the communications code inside them will still refer to the original factory names for each other, which can prevent them from properly communicating. This could result in FB showing Unread Message notifications, even though Messenger has consumed them. I... am not sure how to get around this, but perhaps someone who's had to deal with this directly can provide more insight.

All About Messenger

....

You will keep getting Message Notification in FB-LC app even if you don't install messenger, But you won't able to see those message as FB will Redirect/Force you to download messenger (-_-)

If you are not heavy FB Messenger user, you can try http://mbasic.facebook.com/messages in browser/chrome when you get notification to see/reply, as i do. (Bookmark that link for easier access) Otherwise read below....

2. How to Use/Update Messenger with FB-LC

You need to sign FB-LC & Messenger (or any other FB app with same signing key

3. But..But...WHY ?

1. All Facebook-related applications (including FB for Android, Messenger, Pages Manager, etc) on any given phone must be signed using the same key. This is what allows them to talk to each other (in terms of account / notification info), despite technically being separate applications. Normally, when you install FB and Messenger (and other stuff) from the Play Store, this is not a problem, because these apps are already signed by the same key. However, any modded version of FB (such as what is posted here) will be signed with the key of the person who modded it. Therefore, when installing a modded FB app, it is necessary to uninstall *all* other FB applications (including Messenger) prior to installing the modded FB app.

2. So, If you wish to install a Messenger app along side the modded FB app, you have two options:

A) The first post in this thread contains links to Messenger (and other FB-related apps) that have been re-signed with the same key as Facebook LC. This allows them to coexist (and co-operate) on the same phone without issues.

B) You can grab the APK for Facebook LC, the APK for any version of Messenger you like, generate your own signing key, sign them BOTH with the key you generated, and install them both on your phone. This will work just as easily. The upside is that you have more choices over which exact version of Messenger to install, but the downside is having to go with manually signing.

4. How to Sign APKs ?

Steps

Uninstall all the FB apps from your phone including FB-LC

Download apk from apkmirror (messenger) & FB-LC from OP (if not already)

Sign all these APKs with "test key" (use windows tool for faster signing because zip signer will take half an hour to sign all these)

Install these signed APKs

Details

Windows , (I suggest this option as it'll be much faster)

You need Java installed in windows.

Download it from here..https://java.com/en/download/manual.jsp

Use,

https://xdaforums.com/showthread.php?t=2478180

OR

Android

https://play.google.com/store/apps/details?id=kellinwood.zipsigner2&hl=en

# Use test-key. Sign with same key to ALL your Facebook apps, FB-LC, Messenger, Lite apps or any other you are using.

# You need to sign FB-LC only once before installing (whenever new version comes)

For Messenger and all, You have to sign them whenever you want to update it with same key that you used in FB-LC (test-key in this case).

# After signing first time you need to Uninstall PlayStore version of all FB apps & original FB-LC before you install your signed apks.

As cross signature installation is not possible.

# Once you install your signed version you can update them with your future signed version (test-key) without uninstall

# After signing Messenger you won't get update via play store. So, you need to use apkmirror whenever you want to update & sign it. You can grab updated apk from here. https://www.apkmirror.com/apk/facebook-2/messenger/

PS : You can zipalign APKs after signing for better ram management. Read Here.(it's not mandatory but recommended).