Latest Facebook Messenger 116 user agents:

User Agent Platform Device
Mozilla/5.0 (Linux; U; Android 4.2.2; pt-pt; ALCATEL ONE TOUCH 7041X Build/JDQ39) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.2 Mobile Safari/534.30 SVN/070FPG1 [FB_IAB/MESSENGER;FBAV/116.0.0.18.70;] Android 4 One Touch Pop C7
Mozilla/5.0 (Linux; Android 6.0; ROBBY Build/MRA58K; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/58.0.3029.83 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/116.0.0.18.70;] Android 6 Robby
Mozilla/5.0 (Linux; Android 6.0; mobiistar_LAI_Yuna_S Build/MRA58K; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/58.0.3029.83 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/116.0.0.18.70;] Android 6 Lai Yuna S
Mozilla/5.0 (Linux; Android 6.0.1; SM-G920F Build/MMB29K; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/58.0.3029.83 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/116.0.0.18.70;] Android 6 Galaxy S6
Mozilla/5.0 (Linux; Android 5.1.1; SM-J500FN Build/LMY48B; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/58.0.3029.83 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/116.0.0.18.70;] Android 5 Galaxy J5 (2015)