Windows Phone does not have a native YouTube app, which means any time Google makes a change 3rd party developers have to scramble to update their apps and return them to compatibility.
Today two Windows Phone 3rd party YouTube apps has seen updates to address an issue related to a new signed video algorithm which affects Vevo music videos.
Tubecast has been updated to version 18.104.22.168 to address this issue, and SuperTube has seen a similar update to version 22.214.171.124 for the same reason.
Both apps are high quality YouTube clients, with SuperTube in particular making it easy to cache YouTube videos for offline playback, while Tubecast being extremely powerful when it comes to streaming videos to wireless displays including Chromecast, Apple TV and DLNA.
The apps can be found at the links below.