Latest Facebook Lite 21 user agents:

User Agent Platform Device
Mozilla/5.0 (Linux; U; Android 4.1.2; pt-pt; GT-S5280 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30[FBAN/EMA;FBLC/pt_PT;FBAV/21.1.0.17.137;] Android 4 Galaxy STAR
Mozilla/5.0 (Linux; Android 7.0; PRA-LA1 Build/HUAWEIPRA-LA1; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/87.0.4280.66 Mobile Safari/537.36[FBAN/EMA;FBLC/ru_RU;FBAV/21.1.0.17.137;] Android 7 P8 Lite (2017)
Mozilla/5.0 (Linux; Android 5.1.1; SM-J320FN Build/LMY47V; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/46.0.2490.76 Mobile Safari/537.36[FBAN/EMA;FBLC/pt_PT;FBAV/21.0.0.15.137;] Android 5 Galaxy J3 (2016)
Mozilla/5.0 (Linux; Android 5.1.1; SM-J320F Build/LMY47V; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/55.0.2883.91 Mobile Safari/537.36[FBAN/EMA;FBLC/pt_PT;FBAV/21.1.0.17.137;] Android 5 Galaxy J3 (2016)
Mozilla/5.0 (Linux; Android 4.4.2; SM-G313HZ Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/30.0.0.0 Mobile Safari/537.36[FBAN/EMA;FBLC/en_US;FBAV/21.1.0.17.137;] Android 4 Galaxy Ace 4 Lite