It's possible that you don't need a fix if you're using a razer/steelseries/zowie/logitech/mionix/cmstorm/asus mouse, just use 6/11 (1:1) and turn off enhanced pointer precision (acceleration), set scaling to 100% (windows 8.1) and use raw input. Then, use 500/1000Hz and 900-1800dpi providing it's a native step on your mouse to be comfortable at 2560x1440.

The fix you reference is only useful for specific games that do not have raw input (or force enhanced pointer precision back on). So, many old ones, or new ones with dumb developers. Unless it's something like the Povohat QL Mouse Acceleration Driver that's used in order to have the same acceleration properties across multiple games, you've probably been told you need a 'mouse fix' such as MarkC's when in reality you don't. For example, it's not needed for Quake Live, Team Fortress 2, Counterstrike: Global Offensive and many others.

To answer your original question, you don't need to change anything with that new resolution, the fix works regardless of that. Since you have it installed, leave it installed, you can only be better off with it.

Aw... Are you telling me this whole time I have been using that fix, and in all actuality it has been a hindrance?

And, you are saying the next time I reinstall Windows, I shouldn't bother using the fix?

Edit: Or is it a required for 1920x1080 resolutions?

Basically, next time you install windows, re-install windows, attend an event and use a new computer, visit somebodies house and use theirs... essentially whenever you use another computer... don't bother fussing over any mouse fix unless a specific game requires it.

If you scroll to "Does my game need a mouse fix?" on the download page it details how to find out.

It won't harm your experience with it installed, it's more a 'safe guard' for games that may require it. In other words, the mouse fix simply covers all bases, just in case, so don't uninstall it. Resolution has absolutely no impact.

When was the last game released that required it?

Does BF4 require it?

BF4 doesn't require it, you can enable 'Raw Input' from the in-game menu by hitting escape, this will bypass Windows.