Very current knowledge is one of the main things I look for when evaluating a potential hire. It not only hints at an ability to learn, but also at a passion for the industry. I think that's where a lot of ageism comes in to play. I personally worked at two enterprise dev shops where the older engineers didn't give a hoot past what they had learned years ago and managed to stay writing ever since. Their code might potentially have been more stable but it also was slower, had a hell of a lot of unnecessary boilerplate, was a pain to navigate, and couldn't actually do much anything impressive because it was working with such a minimal toolset.

I'd say focus as much as you can with your resume on highlighting those current library/framework/patterns that you're passionate about. Those are often times the things that recruiters will look for as well (in addition to the basics).