I recently update to 12.5.4 on download gets stuck @ 0%. I had to downloaded because the app wouldn’t open after the update. I have the paid version since 2019. I’m on iPad mini 2. I know, lil’ old but gets the job done of reading hundreds of comics and books, which is the only thing I do on it. I also sent a video by email to the Panels app team with the issue. Does anyone else have a solution or tips to share? Thanks.
iOS 14 is the minimum requirement.
We’ve opened a ticket to Apple’s tech support. We don’t know if it’s a bug on the AppStore or what, but they’re reporting the app is compatible with iOS 11 and higher, and the AppStore is allowing downloads from incompatible versions. They told us they are investigating the problem because it looks like everything is correct on our end.
Apparently, this has been happening way before the latest update.
Sorry for the inconvenience, but we can’t do much 
As Sachin correctly pointed out, the minimum required version for the latest build is 14.1
Apparently, it’s fixed already. I’m unsure if Apple is having replication problems in their AppStore servers, but it took 7 days for them to update the minimum required version.
Without any change on our side, it looks like it’s fixed and now the AppStore is showing the correct minimum version