I'd make a big distinction between entirely new languages, tool and frameworks and simply keeping up with the changes in a reasonably mature environment. For something that is still actively developed, and not in maintenance mode, it is a bad sign if it is on a very old version of that environment. There are a lot of nuances here depending on how disruptive, but also how useful the changes in new versions are.

If you're far enough behind, you get problems with tools and dependencies that stopped supporting the old stuff. That can get very painful and annoying. I'd be generally careful about chasing all the shiny and new stuff, but there is also risk in lagging behind too far once it seems like most people jumped ship.