Upgrading jQuery: Working Towards a Healthy Web | Official jQuery Blog
Working in the environments I do, I can tell you there are some scary situations out there with regards to jQuery. I remember John Resig, more than a decade ago, talking about wanting multiple different versions of jQuery to be able to work on the same page (Scary? Cool!) and I have seen (in 2024!) four versions of jQuery on the same page. Everything worked! That was the good part. The bad part? At least two of those versions had existing security issues associated with them.
At least the page was still working?
The fact that two of the versions on the page had existing security issues is a perfect illustration of why it’s important to keep your dependencies up to date. Pre-npm, pre-depdendabot codebases are especially susceptible to this sort of issue, but… neglected modern codebases are just as much of an issue.
Keep your dependencies up to date!