Latest Facebook Messenger 140 user agents:

User Agent Platform Device
Mozilla/5.0 (Linux; U; Android 4.3; pt-pt; HUAWEI G6-L11 Build/HuaweiG6-L11C02B120) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 4 Ascend G6
Mozilla/5.0 (Linux; U; Android 4.2.2; fr-fr; SM-G386F Build/JDQ39) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 4 Galaxy Core LTE
Mozilla/5.0 (Linux; U; Android 4.1.2; sk-sk; LG-P760 Build/JRO03L) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 4 P760
Mozilla/5.0 (Linux; U; Android 4.0.4; en-us; HTC One X Build/IMM76D) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 4 One X
Mozilla/5.0 (Linux; Android 7.0; SM-G925F Build/NRD90M; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/61.0.3163.98 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 7 Galaxy S6 Edge
Mozilla/5.0 (Linux; Android 7.0; HUAWEI VNS-L31 Build/HUAWEIVNS-L31; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/59.0.3071.125 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 7 P9 Lite
Mozilla/5.0 (Linux; Android 6.0; STARTRAIL 8 Build/MRA58K; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/61.0.3163.98 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 6 StarTrail 8
Mozilla/5.0 (Linux; Android 6.0.1; VFD 600 Build/MMB29M; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/62.0.3202.84 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 6 Smart Prime 7
Mozilla/5.0 (Linux; Android 6.0.1; VFD 600 Build/MMB29M; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/59.0.3071.125 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 6 Smart Prime 7
Mozilla/5.0 (Linux; Android 6.0.1; SM-J510FN Build/MMB29M; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/61.0.3163.98 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 6 Galaxy J5 (2016)
Mozilla/5.0 (Linux; Android 6.0.1; Redmi 4X Build/MMB29M; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/61.0.3163.98 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 6 Redmi 4X
Mozilla/5.0 (Linux; Android 5.1; HUAWEI CUN-L01 Build/HUAWEICUN-L01; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/62.0.3202.84 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 5 Y5II
Mozilla/5.0 (Linux; Android 5.1; HUAWEI CUN-L01 Build/HUAWEICUN-L01; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/61.0.3163.98 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 5 Y5II
Mozilla/5.0 (Linux; Android 5.1.1; SM-J320FN Build/LMY47V; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/61.0.3163.98 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 5 Galaxy J3 (2016)
Mozilla/5.0 (Linux; Android 5.1.1; HUAWEI SCL-L21 Build/HuaweiSCL-L21) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/39.0.0.0 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 5 Y6
Mozilla/5.0 (Linux; Android 5.1.1; Hisense L678 Build/LMY47V; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/61.0.3163.98 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 5 L678
Mozilla/5.0 (Linux; Android 5.1.1; C6903 Build/14.6.A.1.216; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/61.0.3163.98 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/140.0.0.43.91;] Android 5 Xperia Z1