The world of Internet services moves at a pace and it's not surprising that older platforms don't get on fully with the latest services and APIs. In this case it's the official Twitter client for Windows Phone 8.1 that has stopped working - we did know that this might happen at the start of June, according to Twitter's own announcements. You'll remember that they ? Don't panic if you're on 8.1 though, third party clients come to the rescue.