OMG! I don't think I've ever seen that button before! It definitely worked! Marvin is up and running all my backed-up books installed, and no banner taking up any screen space!!!
For anyone as
ignorant uninformed as I was, here are a few steps to reinstall Marvin even though it is no longer available on the Apple store:
1) Download and install
iMazing. I was able to do this with the free version of iMazing although there was a report here that you needed the paid version, ymmv.
2) Follow the directions in
this video to install Marvin.
- you either need to have a current version of Marvin installed on another device to extract the .ipa file ---OR--- you can extract the "Marvin.imazingapp" file from an older iOS backup!!
Attachment 204298
Steps 3 and 4 are optional if you want to restore books from a Marvin backup.
3) Once you have Marvin installed you can use imazing to drag your marvin.m3backup file (the backup of epubs that Marvin makes) to your documents folder in Marvin.
Attachment 204297
4) In Marvin, goto settings (sprocket in top left corner), select "General settings", scroll all the way to the bottom to "ADVANCED (BE CAREFUL)" and select "Backup and restore". Then select "Restore a backup". If you have your marvin.m3backup file in your Marvin documents folder from the previous step, then it will restore all the books from the time that backup file was made. WARNING: this is destructive and will remove any books you currently have in Marvin....which honestly shouldn't be any if you are trying to install a fresh version of Marvin

... anyway, if there are any books you want to save, do it before accomplishing this step.
5) To remove the banner at the bottom of the screen: go to settings and select "Support Marvin", scroll all the way to the bottom and select the "Restore previous tips" tag. That may, or may not, say it was successful, but the banner should be gone.
Attachment 204296
Voila! You have a fully functional Marvin restored to your iThing!
I HIGHLY recommend going into your iThing settings and DISABLE Apple's 'feature' to offload unused apps.
6) goto iOS settings, scroll down to "App Store" and deselect (turn off) "Offload Unused Apps". Be aware
you will be responsible for removing any apps you don't want if you start running out of space on your iThing.
Attachment 204295
Cheers!
OBTW: We should probably change the title of this thread from "So Marvin's Gone!" to "We thought Marvin was Gone, but we are smarter than Apple!" (or at least more perseverant...)