> So you are saying that other people mostly delete old versions from
> ~/.emacs.d/elpa/, and that's why this problem was not reported until
> now, is that right?
Right.
> What are our recommendations, if any, for cleaning up old versions of
> ELPA packages?
I had old versions of packages mostly because I had problems with moving between emacs versions in the past.
For example, I had to roll back some package versions along with emacs version downgrading (after unsuccessful upgrade).
But now my config is stabilized and I just deleted old versions manually a few days ago.