and later. FaceTime streaming over cellular data is unavailable for the iPhone 4 and the iPad 2. Walkie-Talkie Walkie-Talkie is a limited FaceTime Audio-based communication feature made available on September 17, 2018, for Apple Watch devices running watchOS 5.0 or later. The application allows users to have two-person calls similar to using a real walkie-talkie, as conversations are push-to-talk and only one end of the conversation can speak at a time. Walkie-Talkie is intended for short and quick messages between two people rather than long conversations which are better suited for traditional phone or video calls. Users can set their availability for walkie-talkie through the control panel or in the app itself, which allows friends to start a call at any time. In July 2019, Apple temporarily disabled the Walkie-Talkie feature from all Apple Watches after a vulnerability was discovered that allowed a user to listen to another person's iPhone without consent. Limited availability By country , FaceTime was not enabled on devices bought in the United Arab Emirates possibly due to regulations in this country that restrict IP-based communications. FaceTime is made available for iPhones in the United Arab Emirates upon updating iOS 13.6. In addition, iPhone and iPad (Cellular models) devices bought in mainland China have FaceTime Audio, Group FaceTime, and the ability to create and join FaceTime links via the FaceTime app disabled, while FaceTime Video is available. Devices bought outside these countries support both video and audio versions of FaceTime. Although Egypt, Jordan, Qatar, and Kuwait originally disabled FaceTime on the iPhone 4, they later re-enabled the feature through a carrier update for existing phone owners and made it pre-enabled on any newly purchased iPhone. In March 2018, FaceTime was made available for iPhones in Saudi Arabia upon updating to iOS 11.3, and in August 2019, FaceTime was made available for iPhones in Pakistan upon updating to iOS 12.4. By iOS version As of April 16, 2014, FaceTime ceased working on earlier versions of iOS that had previously supported it (iOS 4 and later), due to the client-side certificate used to authenticate a genuine Apple device with FaceTime servers (amongst other uses) expiring on that date. Apple chose not to release an update to this certificate for all devices for which a newer major iOS version (with a new, valid certificate) was available. Apple did release a minor update, to the certificate only, for all OS