It's simple enough to install an older version of a NuGet package into a particular project (see this answer).
However, I can't figure out a way to do this solution-wide.
This is a common enough case now since jQuery went to the parallel 1.x / 2.x release model, where there is a current 1.x release and a current 2.x release which supports only the modern browsers. NuGet only shows the 2.x releases as current, making updating 1.x release a big pain.