Note that Google ceased sign-in support for Android 2.3.7 and older in 2021, which may complicate account management on these devices. Alternatives to Messenger for Android 2.3.6
Because you are installing an app from outside the Google Play Store, you must enable "Unknown Sources." download old version of facebook messenger for android 2.3.6
If your legacy phone's browser can still render modern search engines: Connect your phone to a stable Wi-Fi network. Navigate to Uptodown or APKMirror. Download the compatible version directly to your device. Note that Google ceased sign-in support for Android 2
Alternatively, a much better option for weak, older hardware is . The early versions of Messenger Lite are lightweight, use less RAM, and are much more likely to successfully bypass server blocks on old operating systems. Trusted APK Repositories a much better option for weak