Mouse navigation was never supposed to be a part of this game, so it eventually got removed, yes. It caused too many issues. Does your keyboard's numpad still work? In that case, you can still move using the 4-8-6-2 buttons (4 for left, 8 for up, 6 for right and 2 for down). If you absolutely HAVE to rely on mouse controls, use this tutorial https://spedumon.itch.io/small-on-top/devlog/628915/mouse-wont-work-in-new-publi...