Ask HN: Why Had Skype Been Removed From The iOS App Store?

I just recently noticed there was an update from skype, with various new features added. Of course, I decided to download the update, so I tapped on the "update" button. However, a message pops up saying "This Item has been removed". I wondered if it was some sort of glitch (I changed from one Apple ID to another recently), so I decided to delete the app and re-download it. Surprisingly, it wasn't there in the App Store at all. What would cause Microsoft to remove it (perhaps temporarily, perhaps permanently) from the App Store?