Barnes & Noble officially closed Nook Appstore on March 15, 2016. You can read the announcement at https://nookdeveloper.barnesandnoble.com/
The closure isn’t a complete surprise because sales have dwindled a lot in the past years. But we’re still sad to see it go as we have had very good successes with their stores and it was one of the first stores where we begin to sell apps and achieve great numbers. Some of our apps even reached the Top 10 in their store best sellers.
If you have one of our apps in Nook, please keep enjoying them. If you need technical support, we continue to offer them. Please write to us via the Contact Us form on permadi.mobi.
Also keep in mind that Nook HD and their newer devices (which are made by Samsung) do support Google Play, so if you have one of those, you can still get our apps from Google Play. Read more: http://www.cnet.com/news/barnes-noble-adds-google-play-store-to-its-tablets/