If you own a smart TV or an iOS gadget that is getting somewhat long in the tooth, you may need to do some upgrading this if you need to keep using the YouTube application. Because of specific changes in the application’s API, it’ll no more deal with various models models in 2012 or before, including second-generation Apple TVs, Panasonic TVs, Sony TVs and Blu-ray players, and in addition devices running Google TV versions 1 or 2. You’ll know you’re affected if a video showing the notice above plays after starting up the application, however most models released in 2013 or later are safe.
Now, if you want continued with access to the YouTube application, you’ll need to update iPhones, iPads and iPods to iOS 7, at least. Third-gen Apple TVs need a platform upgrade, too, while Google TV version 3 or 4 gadgets need the most recent application update available on Google Play. Just because your item is excessively old for upgrades doesn’t mean you’ll need to bid your YouTube binges farewell, though. The website still loads on Safari (even on older iOS devices) or on any smart TV browser than supports flash/HTML5.
Source : YouTube Help