Aha, but you had to create an update!
I was just adding a v22 folio(with library tag) to existing v21 or older folios and the Icon was not appearing.
I will wait to know what big magazines will do with old published folios. Will they stay without filter (if above mentioned behaviour is fixed and the icon will appear when mixed folio versions) or will there be soon magazines with the update button beside of every old published issue?
Yes you can mix non-tagged and tagged folios. But my custom viewer will not show the Icon until old folios have been updated (even with the old same folio version).
Enough of betatesting for this morning. There are now enough bugs which Adobe needs to fix in the next days (not weeks, months or release versions!!).
Due to the problems, I was installing the plugins, viewer builder and the custom content viewer again.
I can't repoduce it again. But I'm pretty much sure that it was the same scenario as for the problem with folios not showing.
Maybe it was resolved after I reinstalled the App completely on the iPad.
Thanks for testing