What do you mean stay up to date? From my experience I've noticed that if they dig deep and understand the underlying fundamental concepts of the trade, there's

What do you mean stay up to date? From my experience I've noticed that if they dig deep and understand the underlying fundamental concepts of the trade, there's not many programming problems, platforms, or languages, that couldn't be learned in the span of a few days. The longer I go, the more I realize that everything that seems new and fresh was most likely already invented in some capacity before I even wrote my first line of code. I completely understand if they are non flexible and still choosing out of date frameworks or libraries that aren't necessarily used any more, however the ability to compare and contrast frameworks and languages and choose the one based on a deep understanding of the underlying implications seems to me more important than being fluent in the latest platforms.