What happened to the iPad app 'Downloader'?

[Minion]

I brought this app when I first became an iPad user in April this year. It is no longer available at the App Store, nor it is listed In the 'Purchased' tab even though the app is still on my iPad. Is this how a normal practice how App Store treats apps that are pulled? I suppose I won't get any support or future upgrades for this app. If the app does not work with any future release of ios, I am out of luck, correct?