Comixology has suspended development and has pulled the dedicated GI JOE, True Blood and Doctor Who apps from the Apple App Store. Anyone with an iOS device, such as the iPad, iPhone or iPod Touch will have to download the official Comixology app in order to purchase new issues and sync existing content.
If you have purchased single issue or graphic novels from the dedicated GI JOE app, you will have to now download Comixology. If you don’t have an existing account, you can register a new one and then import the comics into your main account via sync. This will storage your comics in the main Comixology Cloud and allow you access them on more devices.
Comixology has not elaborated on why they pulled these dedicated apps from the main iOS App Store. Likely, they are trying to encourage people to use their flagship app, where more content is available and customers would be more prone to make impulse buys.