As of version 2.0.0 the Sort function hasn't been removed. Here are some reasons why perhaps you aren't seeing it.
- If you're using a controller, there are no green, clickable Sort buttons at the top of the backpack or Storage menus. Instead, there are instructions onscreen telling you which controller buttons to press. Note that in most cases it involves pushing the left control stick "into" the controller until it clicks. (Some platforms refer to this as the "L3 button".)
- If you're NOT using a controller (i.e., you're using the mouse or a touchscreen), then there should be clickable, green Sort buttons at the top of the backpack and Storage menus.
- If you switch from controller to non-controller or vice-versa after the menu is opened, the game might get confused and not show the right things. Close the menu to un-confuse things, then open the menu again with your desired interaction medium and you should see the proper buttons/hints.
- There are layout issues in some languages where the clickable Sort button or the controller hints get laid out offscreen.
- The controller's L3 button should still work.
- If you can't use a controller with the game but you're able to read another language, consider switching to that language temporarily until the problem is resolved. English is the best-tested language for this game, so that's probably the one I'd try first if you're able to read English.