What is worth relearning
Recent OBS releases have reworked the audio mixer, including easier monitoring and pinning, and they have kept pushing output options such as more than one encode path. WebRTC-style outputs and the websocket are how other apps talk to OBS. If a button moved, you are not bad at streaming. The panel moved.
After you update, check mic monitoring, the recording track versus the stream track, and any plugin that hooks the old UI. Update plugins on purpose, one at a time, so you know which one broke the scene.