I remember in the past there was a feature to check which issues were missing in a set with at least one owned issue. is this functionality gone or restricted behind membership subscription? my app is in a grandfather unlocked state. what exactly are the differences between unlocked grandfather state and not unlocked grandfather state?
To use the missing comics screen you need an active subscription indeed (grandfathered will not suffice). The same goes for the automatic key comic info (and updating it), and the NCBD tab in the Add Comics screen.
When you open your app’s menu top left, and tap on the “Subscription Status” bit, you can read more about it, or take out a subscription.
Am I understanding this correctly; generally speaking grandfather unlock essentially just lets a paying customer, who helped financially support the app in early stages, use the software (which I’m guessing is free since there are paid subscriptions) and add comics by search against their database?
For NEW users, CLZ Comics has become a subscription app in Sept 2019, with the release or version 5.0. So since then, new users have to pay for the subscription to use the app and its online services.
For you however, because you had purchased the app before that date, you have been grandfathered under the old policy and you received a free life-time app unlock, to use the app and its essential online services (Core/Cloud).
You do not need to pay for the subscription.
So basically, you have been allowed to use the app without paying anything, for at least 5 years. Maybe even longer.
Including all functionality that you had before v5.0. You did not lose anything. On top of that you still got to download and enjoy all app updates in the past 5 years, all free of charge.
The only things you did NOT get for free are the NEW and EXTRA online services introduced in version 5.0 and later updates:
finding missing comics using the Missing Comics tool