Somewhat related to #10789, our version menu is getting pretty long (and if we don't do anything about it, it will get too long rather soon):

I propose that in addition to devel and stable, we only show five previous versions and then maybe a link to a page with older versions. Alternatively, we might just drop older versions altogether – or is there a particular reason why someone would want to use the documentation for MNE-Python that's over 3 years old?