Latest Facebook Messenger Lite 263 user agents:

User Agent Platform Device
Mozilla/5.0 (iPhone; CPU iPhone OS 13_4_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML like Gecko) Mobile/15E148 LightSpeed [FBAN/MessengerLiteForiOS;FBAV/263.0.0.43.121;FBBV/212338128;FBDV/iPhone9 4;F iOS 13 iPhone
Mozilla/5.0 (iPhone; CPU iPhone OS 13_4_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 LightSpeed [FBAN/MessengerLiteForiOS;FBAV/263.1.0.76.121;FBBV/213025676;FBDV/iPhone12,1;FBMD/iPhone;FBSN/iOS;FBSV/13.4.1;FBSS/2;FBCR/;FBID/phone;FBLC/de_AT;FBOP/0] iOS 13 iPhone 11
Mozilla/5.0 (iPhone; CPU iPhone OS 12_4_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 LightSpeed [FBAN/MessengerLiteForiOS;FBAV/263.1.0.76.121;FBBV/213025676;FBDV/iPhone9,3;FBMD/iPhone;FBSN/iOS;FBSV/12.4.1;FBSS/2;FBCR/;FBID/phone;FBLC/sv_SE;FBOP/0] iOS 12 iPhone 7