While this is the best exclusive version for Android 4.1.2, you must manage expectations:
The final official version that supported Android 4.1.2 is Facebook v191.0.0.34.70 (released in mid-2019). While it lacks today’s Reels, Avatars, and advanced AR filters, it offers a rock-solid experience: facebook for android 412 free download exclusive
Available on F-Droid, Frost is a lightweight wrapper that uses the mobile website but wraps it in a clean interface. It works perfectly on Jelly Bean and uses half the RAM of Facebook Lite. While this is the best exclusive version for Android 4