Latest Facebook Messenger Lite 333 user agents:

User Agent Platform Device
Mozilla/5.0 (iPhone; CPU iPhone OS 14_7_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 LightSpeed [FBAN/MessengerLiteForiOS;FBAV/333.0.0.35.113;FBBV/322198019;FBDV/iPhone10,6;FBMD/iPhone;FBSN/iOS; iOS 14 iPhone X