Latest Facebook Messenger 125 user agents:

User Agent Platform Device
Mozilla/5.0 (Linux; Android 6.0; U FEEL LITE Build/MRA58K; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/59.0.3071.125 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/125.0.0.22.70;] Android 6 U Feel Lite
Mozilla/5.0 (Linux; Android 6.0.1; SM-G532MT Build/MMB29T; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/59.0.3071.92 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/125.0.0.22.70;] Android 6 Galaxy J2 Prime (TV)
Mozilla/5.0 (Linux; Android 5.1; A1601 Build/LMY47I; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/59.0.3071.125 Mobile Safari/537.36 [FB_IAB/MESSENGER;FBAV/125.0.0.22.70;] Android 5 F1s