Latest Facebook 503 user agents:

User Agent Platform Device
Mozilla/5.0 (Linux; Android 15; SM-A356B Build/AP3A.240905.015.A2; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/145.0.7632.122 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;] Android 15 Galaxy A35 5G
Mozilla/5.0 (Linux; Android 13; SM-A145R Build/TP1A.220624.014; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/145.0.7632.159 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;] Android 13 Galaxy A14
Mozilla/5.0 (iPhone; CPU iPhone OS 18_3_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/22D82 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone12,3;FBMD/iPhone;FBSN/iOS;FBSV/18.3.2;FBSS/3;FBID/phone;FBLC/en_US;FBOP/5;FBRV/708854960;IABMV/1] iOS 18 iPhone 11 Pro
Mozilla/5.0 (iPhone; CPU iPhone OS 26_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/23C55 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone17,1;FBMD/iPhone;FBSN/iOS;FBSV/26.2;FBSS/3;FBID/phone;FBLC/en_US;FBOP/5;FBRV/708854960;IABMV/1] iOS 26 iPhone 16 Pro
Mozilla/5.0 (iPhone; CPU iPhone OS 18_7_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/22H124 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone14,7;FBMD/iPhone;FBSN/iOS;FBSV/18.7.2;FBSS/3;FBID/phone;FBLC/en_US;FBOP/5;FBRV/708854960;IABMV/1] iOS 18 iPhone 14
Mozilla/5.0 (iPhone; CPU iPhone OS 26_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/23D127 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone15,4;FBMD/iPhone;FBSN/iOS;FBSV/26.3;FBSS/3;FBID/phone;FBLC/en_US;FBOP/5;FBRV/708854960;IABMV/1] iOS 26 iPhone 15
Mozilla/5.0 (iPhone; CPU iPhone OS 26_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/23D8133 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone18,4;FBMD/iPhone;FBSN/iOS;FBSV/26.3.1;FBSS/3;FBID/phone;FBLC/en_US;FBOP/5;FBRV/708854960;IABMV/1] iOS 26 iPhone Air
Mozilla/5.0 (iPhone; CPU iPhone OS 16_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/20G75 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone13,4;FBMD/iPhone;FBSN/iOS;FBSV/16.6;FBSS/3;FBID/phone;FBLC/it_IT;FBOP/5;FBRV/708854960;IABMV/1] iOS 16 iPhone 12 Pro Max
Mozilla/5.0 (iPhone; CPU iPhone OS 26_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/23D8133 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone17,2;FBMD/iPhone;FBSN/iOS;FBSV/26.3.1;FBSS/3;FBID/phone;FBLC/en_US;FBOP/5;FBRV/708854960;IABMV/1] iOS 26 iPhone 16 Pro Max
Mozilla/5.0 (iPhone; CPU iPhone OS 26_2_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/23C71 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone14,3;FBMD/iPhone;FBSN/iOS;FBSV/26.2.1;FBSS/3;FBID/phone;FBLC/en_Qaau_US;FBOP/5;FBRV/708854960;IABMV/1] iOS 26 iPhone 13 Pro Max
Mozilla/5.0 (iPhone; CPU iPhone OS 26_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/23D8133 [FBAN/FBIOS;FBAV/503.0.0.56.104;FBBV/704769221;FBDV/iPhone12,1;FBMD/iPhone;FBSN/iOS;FBSV/26.3.1;FBSS/2;FBID/phone;FBLC/en_US;FBOP/5;FBRV/708854960;IABMV/1] iOS 26 iPhone 11
Mozilla/5.0 (Linux; Android 9; ZT216_1 Build/PPR1.180610.011; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/131.0.6778.200 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;] Android 9 ZT216
Mozilla/5.0 (Linux; Android 9; W-P311-EEA Build/PPR1.180610.011; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/134.0.6998.50 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;IABMV/1;] Android 9 View 3
Mozilla/5.0 (Linux; Android 9; UMIDIGI X Build/PPR1.180610.011; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/134.0.6998.50 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;IABMV/1;] Android 9 X
Mozilla/5.0 (Linux; Android 9; U70B Build/PPR1.180610.011; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/134.0.6998.50 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;IABMV/1;] Android 9 U70B
Mozilla/5.0 (Linux; Android 9; Trekker-X4 Build/PKQ1.190414.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/134.0.6998.50 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;] FBNV/500 Android 9 Trekker-X4
Mozilla/5.0 (Linux; Android 9; Trekker-X4 Build/PKQ1.190414.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/134.0.6998.50 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;] Android 9 Trekker-X4
Mozilla/5.0 (Linux; Android 9; Trekker-X4 Build/PKQ1.190414.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/134.0.6998.50 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;IABMV/1;] FBNV/500 Android 9 Trekker-X4
Mozilla/5.0 (Linux; Android 9; Trekker-X4 Build/PKQ1.190414.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/134.0.6998.50 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.69.76;IABMV/1;] Android 9 Trekker-X4
Mozilla/5.0 (Linux; Android 9; TECNO KB3 Build/PPR1.180610.011; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/135.0.7049.111 Mobile Safari/537.36 [FB_IAB/FB4A;FBAV/503.0.0.61.109;] Android 9 Camon iSky 3