The game will automatically force 16:9 with either pillars or letterbox. if your game is not run in ultrawide. you can set ultrawide in the follow steps:
Thanks to Jones’ comment, we add the 3840*1080 in May 2021.
Ultrawide
1 – Go to the Path to game\ThePed_Win_64-Data\managed
2 – Find Assembly-CSharp.DLL and open it in a Hex Editor. I used HxD
3 – Press CTRL+R and click on the Hex-Values tab.
4 – Under Search for type “39 8E E3 3F”
5 – Under Replace for type “26 B4 17 40”
6 – Replace all instances of “39 8E E3 3F” that you can find, replace it 4 times in total.
7 – Save the file.
2 – Find Assembly-CSharp.DLL and open it in a Hex Editor. I used HxD
3 – Press CTRL+R and click on the Hex-Values tab.
4 – Under Search for type “39 8E E3 3F”
5 – Under Replace for type “26 B4 17 40”
6 – Replace all instances of “39 8E E3 3F” that you can find, replace it 4 times in total.
7 – Save the file.
21:9 (2560×1080)ㅤㅤㅤㅤㅤㅤ26 B4 17 40
21:9 (3440×1440)ㅤㅤㅤㅤㅤㅤ8E E3 18 40
21:9 (3840×1080)ㅤㅤ 39 8E 63 40
21:9 (3840×1600)ㅤㅤㅤㅤㅤㅤ9A 99 19 40
By Gardemi14
Add this to your article — (3840×1080)ㅤㅤ39 8E 63 40
thanks, I had added it.