While newer Android versions receive the most advanced UI updates, many core features remain available for Android 5.1: Scroll through updates from friends and pages.
Visit a trusted repository like APKMirror or Uptodown to find a version compatible with Android 5.1+.
Typically ranges from 80 MB to 150 MB depending on the specific build. DPI Support: Covers a wide range from 280 to 640 DPI . How to Install Facebook APK on Android 5.1
Since the Google Play Store may occasionally limit the "latest" version for older devices, manual installation via APK is a common workaround.
It is designed for 2G/3G networks and devices with as little as 2GB of RAM.