There is a new app. Try downloading again from the App Store or updating the one you have on your iPad. This one is run by Future, and once you sign in, you can go to the help section and click on the link to restore purchases and that will enable you to have access to all your previous issues (you'll have to re-download them all).
There is also a special Pink Floyd retrospective issue available in that app. I was able to access it for free once I purchased the latest issue (I don't have a yearly sub, I just buy each issue separately).
Bookmarks