Many unofficial apps for YouTube on iOS were using not allowed APIs from Google. It means that you could play 60 FPS videos, watch videos in 4K resolution (if available), background playback, audio-only mode (which was useful while hearing music from YouTube without video to save free datas on mobile plan), and, the most important, to block ads. Now it looks like these times are over.
I was using ProTube, which I reviewed HERE. Beside official YouTube app from Google, ProTube was capable of playing supported videos with 60 FPS and using 4K resolution, if available. As I know, no other 3rd party app on App Store could do this. Currently, the only way to enjoy these features on iOS is to use official YouTube app from Google, which is blown with ads in videos and, unlike ProTube, lacks some handy iOS features. It’s true, that you can get YouTube Red subscription to get rid of the ads and gain some features like background playback, but it’s not available in all countries. Here in Slovakia, I can’t use subscription, because it’s not available in my area.
Google offered to Jonas Gessner, author of ProTube, to offer his app for 10 dollars/month. He did not agree a decided to end development of ProTube. Jonas Gessner could remove key features from ProTube to keep it alive at App Store, but it would make from ProTube another commom app, as many other YouTube apps on the App Store.
You can keep ProTube in your iTunes library, but in the future Google will change APIs – I’m 100% sure – which will break ProTube’s functionality and no update will be available.
It’s interesting, that ProTube was on App Store for very long time without actions from Google. In past, you were able to download videos via ProTube, but this feature was soon removed.
Another category is Picture-In-Picture, which was brought to iPads with iOS 9. It looks like in this mode does not work ads from Google, so it’s possible, that this feature may be removed from many 3rd party YouTube apps on the App Store. As expected, this feature is not present in YouTube official app, even with YouTube Red.
Full statement from Jonas Gessner is avialable on his website.