The two sites I upgraded seem to have gone well, so I did all the others. That turned out to be more complicated, because some of them are spread over more than one computer, and some of them have subdomains.
And then I decided to upgrade one of the computers, which was running Fedora 9, to the current Fedora 27. And that included upgrading the version of perl, and the newer version of perl has things that are no longer allowed, such as defined %array. So I had to change that.
Also, if a page includes something dragged ni from another site, then if that other site isn't using https, then the whole page shows up as "insecure".
So I've fixed that where I can, but in some places, it actually can't be fixed. That's usually a page that references a graphic from another site