As of April 20, 2015, the YouTube app should work with all iPad models except the original. If the app will not work with your iPad you may need to upgrade to iOS 8.2. The YouTube app does not support devices running anything before iOS 7.0. This means that the app will not work on the first- to fourth-generation iPod touch, iPhone 3G, iPhone 3GS and first-generation iPad. All other iOS devices are supported.
Users with older devices can still access YouTube by navigating to m.youtube.com on their mobile browser. The mobile YouTube website will work on all iOS devices including the original iPad.