Starting in late 2020, Facebook began dropping support for Android versions older than 5.0 (Lollipop). That means:

However, Facebook still works on KitKat — you just need the right APK file (Android Package Kit) from a trusted source. The last stable, feature-complete Facebook builds for API level 19 (Android 4.4) deliver a surprisingly good experience when chosen correctly.

Make Facebook feel snappy again on your KitKat device:

🔋 Battery note: Facebook v327 drains about 8-12% per hour on active use on a 2014-era battery. Expect less on newer batteries.

Cause: Hardware acceleration conflict.
Fix:
Go to Settings > Apps > Facebook → Toggle "Disable HW overlays" in Developer Options (needs reboot).

This site provides old versions with user reviews. Look for versions with high user ratings and no "virus detected" flags.

Do not download from random forums or pop-up ads. Use reputable mirrors:

Direct search on APKMirror: “Facebook 327.0.0.32.101”