I was able to upgrade my 1.9.16 from the version that always returned to ads in the bottom carousel, to the newer one with a "sticky" shortlist, by visiting the following thread, downloading the latest 1.9.16, and following the simple instructions.
https://www.mobileread.com/forums/sho...d.php?t=145177
Hooray! My only question is, how does the Kobo pick the books from your shortlist to display in the carousel? It's not by most recent, author, title, or file type. It seems to be random. Anyone know? Thanks.