@
kguil,
I believe one of the biggest issues bothering Marvin users, at least here on MobileRead, is the incompatibility with the calibre plugins which Apple caused in iOS 8.3 (IIRC).
As far as I know, the only current way to use the plugins is on a jailbroken iDevice, using the Cydia hack "House Arrest Fix".
Do you have any idea/plans to recreate a communications channel between Marvin and the calibre plugins? I am sure many of your users would be thrilled -- I was under the impression that one of the biggest draws of Marvin used to be the unparalleled level of interoperability with calibre, and it would be a shame to let Apple break that without at least trying to fix it.
Maybe get in touch with @Philantrop (the current plugin maintainer) to discuss things?