Hm, having looked at a lot of this material that is not my experience at all. There will always be version differences, all material can never be up to date, but “completely outdated”? No, even a lot of UDK material can be translated to UE4 with ease, not to speak of just previous UE4 versions. And in fact, this can actually be a good thing. As it will force you to think, and force you to fiddle and experiment, or if you’re programming and there’s a deprecation you’ll be forced to find another way. This is much better than just mindlessly copying what you see. As soon as there’s a snag your brain has to wake up. Because now you have problem that needs solving, and that’s what game dev is all about.