After upgrading to Unity 2017.1, there is a really noticeable problem when running the game in a resolution different from the native resolution. The entire screen (including 2D and 3D elements) would have ugly jagged lines. You can replicate this on any project by just changing the Game View resolution in the Editor to 640x480 (or some other really low resolution) then upscaling it. It has nothing to do with anti-aliasing or image effects, and this did not happen in previous versions of Unity.
Rust also encountered the same issue. Unity 2017.1 (left) and Unity 5.6 (right).
If this was intentional, can there at least be an option in the Graphics Settings? Thanks.