Blender changes version by version, but the changes are mostly superficial, tools changing the name, buttons gets shuffled around in the UI, etc. Core 3D knowledge stays the same. When you follow a course using the Blender version the course was recorded with, you can follow 1 to 1 with what’s on screen, it’s much easier. The thing is Blender updates way too fast and it’s impossible to keep up with it, so any content you see on the internet will be out of sync if you always have the latest one. And again, the latest one don’t matter as much when it comes to learning. That feeling of missing out because you’re not using the latest version is just that, a feeling, because of the world we live in right now. There’s a good short threat to read that will further clear things up if you’re interested:
https://cgcookie.com/community/18260-learning-through-different-versions-of-blender
