Latest Facebook 52 user agents:

User Agent Platform Device
Mozilla/5.0 (Linux; U; Android 4.3; en-us; ZTE-Z777 Build/JLS36C) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Z777
Mozilla/5.0 (Linux; U; Android 4.3; en-au; GT-I9305T Build/JSS15J) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy S III LTE
Mozilla/5.0 (Linux; U; Android 4.2.2; es-us; GT-S7580E Build/JDQ39) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy Trend Plus
Mozilla/5.0 (Linux; U; Android 4.2.2; es-es; Micromax A47 Build/JDQ39) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 A47
Mozilla/5.0 (Linux; U; Android 4.2.2; en-us; SM-C105L Build/JDQ39) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy S4 zoom
Mozilla/5.0 (Linux; U; Android 4.2.2; en-us; GT-S7275B Build/JDQ39) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy ACE 3
Mozilla/5.0 (Linux; U; Android 4.2.2; en-in; Micromax A114 Build/JDQ39) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 A114
Mozilla/5.0 (Linux; U; Android 4.2.2; en-gb; HTC One XL Build/JDQ39) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 One XL
Mozilla/5.0 (Linux; U; Android 4.1.2; es-us; GT-I9080L Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy Grand
Mozilla/5.0 (Linux; U; Android 4.1.2; es-us; GT-I8550E Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy Win
Mozilla/5.0 (Linux; U; Android 4.1.2; es-us; GT-I8260E Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy Core
Mozilla/5.0 (Linux; U; Android 4.1.2; es-mx; LG-P870 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 P870
Mozilla/5.0 (Linux; U; Android 4.1.2; es-mx; LG-P778 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 P778
Mozilla/5.0 (Linux; U; Android 4.1.2; es-mx; LG-E450f Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Optimus L5 II
Mozilla/5.0 (Linux; U; Android 4.1.2; es-es; GT-I8550E Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy Win
Mozilla/5.0 (Linux; U; Android 4.1.2; en-us; ZTE-Z998 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Z998
Mozilla/5.0 (Linux; U; Android 4.1.2; en-au; LG-D684 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 G Pro Lite
Mozilla/5.0 (Linux; U; Android 4.1.2; en-au; GT-I8730T Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 4 Galaxy Express
Mozilla/5.0 (Linux; Android 5.0.2; VF-895N Build/LRX22G; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/66.0.3359.158 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 5 Smart Prime 6
Mozilla/5.0 (Linux; Android 5.0.2; LG-D722 Build/LRX22G.A1429271654; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/45.0.2454.95 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/52.0.0.12.18;] Android 5 G3S