The full Facebook application has evolved to be quite demanding: Storage Hog
Before downloading an APK, decide which version best suits your device's hardware constraints. Option 1: Standard Facebook (Archived Versions)
There could be several reasons to use an APK file to install Facebook: apk facebook android 5.1
Devices from the Android 5.1 era typically have low RAM. They also feature older processors. The full, modern Facebook app consumes massive resources. Running it on older hardware causes severe system slowdowns. Choosing the Right Facebook Version
Testing conducted on a Samsung Galaxy S5 (Android 5.1.1, 2GB RAM) using Facebook v430.0.0.27.111 revealed the following: The full Facebook application has evolved to be
Open your mobile browser and navigate to a trusted site like APKMirror. Search for "Facebook Lite" or "Facebook".
Since you are not using the Google Play Store, you will need to "sideload" the app. The full, modern Facebook app consumes massive resources
Use the search bar on the repository site to look for "Facebook" or "Facebook Lite".
version or a legacy APK, as the standard Facebook app no longer officially supports this version of Android. Compatibility Overview