Jeff Kaplan (Game Director on Overwatch) made a comment on the subject:
We do not plan to increase the max FOV beyond 103, in any resolution. As a result, this doesn't leave us with a lot of options for 21:9 support. I know this is not the answer our 21:9 players want to hear. But we feel like it ...
Editing the second HEX value mentioned by Brook of Clay did the trick for me. Looks great in ultrawide, though I wish the first person view scaled with the FOV slider - guns just look way too big - though that's a complaint I have with the visuals regardless of aspect ratio. I tried a game online ...
Setting the UI vertical and horizontal scale to 1.02 allows the HUD elements to be slightly nearer to the edges of the screen without cutting off anything. And the new .exe seems to work alright. Great work!
I can't seem to make this work - is it not working anymore? Thanks. 1. Install the file in the OP as per his instructions. 2. Make a copy of the 'default' folder found in dota\resource\flash3\images\hud_skins\ and name that folder 'new_bloom' (without the ')