Today i figured out that with the new flagship mobile devices the Letterbox scale doesnt work anymore. The aspect ratio is 18.5:9? How to solve that problem? Is there any other workaround than rescale the backgrounds of games?
What do you mean "letterbox scale doesn't work"?
If your game is designed for 16:9 aspect ratio, then on 18:9 screen you should get black bars on top and bottom of the screen.
Is this what happens?
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i think best option for you is use scale inner/outer mode