Latest Facebook Messenger 122 user agents:

User Agent Platform Device
Mozilla/5.0 (Linux; Android 9; SM-A102U Build/PPR1.180610.011; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/74.0.3729.136 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/122.0.0.10.69;] Android 9 Galaxy A10e
Mozilla/5.0 (Linux; Android 7.0; SM-G935F Build/NRD90M; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/60.0.3112.107 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/122.0.0.10.69;] Android 7 Galaxy S7 Edge
Mozilla/5.0 (Linux; Android 5.1; VF-696 Build/LMY47I; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/58.0.3029.83 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/122.0.0.10.69;] Android 5 Smart Grand 6
Mozilla/5.0 (Linux; Android 5.1; 8050D Build/LMY47I; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/58.0.3029.83 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/122.0.0.10.69;] Android 5 One Touch Pixi 4 6" 3G Dual SIM
Mozilla/5.0 (Linux; Android 5.0.1; ALE-L02 Build/HuaweiALE-L02) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/37.0.0.0 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/122.0.0.10.69;] Android 5 P8 Lite (2015)
Mozilla/5.0 (iPad; CPU OS 6_1_1 like Mac OS X) AppleWebKit/602.2.14 (KHTML, like Gecko) Mobile/14B100 [FBAN/MessengerForiOS;FBAV/122.0.0.40.69;FBBV/61279955;FBDV/iPad4,1;FBMD/iPad;FBSN/iOS;FBSV/10.1.1;FBSS/2;FBCR/;FBID/tablet;FBLC/vi_VN;FBOP/5;FBRV/0] iOS 6 iPad Air
Mozilla/5.0 (iPad; CPU OS 12_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 [FBAN/MessengerForiOS;FBAV/122.0.0.40.69;FBBV/61279955;FBDV/iPad4,1;FBMD/iPad;FBSN/iOS;FBSV/10.1.1;FBSS/2;FBCR/;FBID/tablet;FBLC/pt_PT;FBOP/5;FBRV/0] iOS 12 iPad Air
Mozilla/5.0 (iPad; CPU OS 10_1_1 like Mac OS X) AppleWebKit/602.2.14 (KHTML, like Gecko) Mobile/14B100 [FBAN/MessengerForiOS;FBAV/122.0.0.40.69;FBBV/61279955;FBDV/iPad4,1;FBMD/iPad;FBSN/iOS;FBSV/10.1.1;FBSS/2;FBCR/;FBID/tablet;FBLC/vi_VN;FBOP/5;FBRV/0] iOS 10 iPad Air
Mozilla/5.0 (iPad; CPU OS 10_1_1 like Mac OS X) AppleWebKit/602.2.14 (KHTML, like Gecko) Mobile/14B100 [FBAN/MessengerForiOS;FBAV/122.0.0.40.69;FBBV/61279955;FBDV/iPad4,1;FBMD/iPad;FBSN/iOS;FBSV/10.1.1;FBSS/2;FBCR/;FBID/tablet;FBLC/en_US;FBOP/5;FBRV/0] iOS 10 iPad Air