As is often the case when dealing with servers, there are outdated versions. The reason is almost always the same: there wasn't enough time to keep things up to date.

It makes sense — sticking to the LTS of anything is hard work. You have a working system, and even if it's a fairly uncomplicated beast, updating dependencies to a new version is rarely simple. It might seem like everything is fine, but then on a Saturday at 01:30, things start breaking down because that once- in-a-blue-moon event without a unit test executes — and it depends on that one deprecated functionality nobody really needed.