Whilst I'm not a fan of it, the term "cyber" is part of the lexicon now, and if you want to communicate to people outside the security industry about it, you'll find it easier when using that term..

It's like the old debates about the term hacker, eventually things become part of common parlance...

As to old knowledge, I'd say it very much depends. Basic principles from 20 years ago apply very much now. The specific attacks may have changed (although in some cases they're still the same) but the underlying concepts remain.