https://wccftech.com/finally-4k-youtube-video-streaming-coming-with-ios-14-on-iphone-and-ipad/

iOS 14 comes with a bunch of new features that users can look forward to. From Home screen widgets to App Clips, Apple brought several design changes to the platform. Soon after the event was over, Apple released the first beta of iOO 14 to developers for testing purposes. We are hearing new changes and additions brought to the platform consistently. Now, we found out that iOS 14 and iPadOS 14 brings 4K resolution to the iPhone and iPad.

As mentioned earlier, iPhone and iPad owners can now stream YouTube videos in 4K resolution. What Apple did is that it added support for the VP9 codec that makes it possible for the device to show 4K videos. Up until now, users were only limited to watch 1080p videos on YouTube.