Hope all is well, I tried the overwriting the .php file in the S2 subdirectory, which left a blank page. I fixed that with a directory renaming. I then noticed in my plugin cpanel in wordpress dashboard that I had 2 versions of s2, I deactivated the old one and deleted it. I installed the latest, 8.7 by the cpanel's Add New. I even installed the HTML version that way about 12 hours ago(10:45pm), why does it have the first notification scheduled to be sent 19 hours later(6:00pm). I did use the blog time as apposed to the utc time when saving a future time.
I reached the product key verifier in the HTML part so I think that's installed correctly. It has the latest version of s2 displaying under the heading.