Apple and Google are preparing to roll out phase two of their Covid-19 contact-tracing system, allowing users to receive notifications about their exposure to infectious people without needing to install a specific app. But the system will still not fully work in Britain until the UK government releases its own contact-tracing app – currently being trialled in the Isle of Wight and the London borough of Newham – nationally. The basics of the “exposure notification” system were built into iPhones and Android devices in May. Users who have downloaded an app made by a public health authority can opt in to a decentralised tracking system. Their phones record details of other devices they have been near, and if one of those users later marks themselves as infectious, exposed individuals receive a notification. Until now, Apple and Google have required users to download an app made by a recognised public health authority to enable the exposure notification system. That has prevented UK residents from using the service, unless they installed a contact tracing-app from another country, such as Ireland or Germany whose apps were available in UK app stores. Even then, they could only use the app passively, since both foreign apps require a diagnosis from their respective health services to mark oneself as infectious. When new versions of iOS and Android are made available, which is expected in the next two weeks, users will be able to join an exposure notification system without needing to download any app at all. They will, however, still need a recognised app to mark themselves as infectious, putting extra pressure on the UK government to move its own app out of beta testing and make it available for general release. But the pressure has diminished in recent months owing to the poor performance of contact-tracing systems in other nations. In June the French government revealed that its contact-tracing app had sent just 14 notifications in its first three weeks of operation, with only 68 people entering a positive test result, despite 2 million downloads. The country was hampered by comparatively low uptake, which the new Apple and Google system is intended to overcome. But in Germany, which uses that system, more than 16 million people have installed the app and only 500 have marked themselves as positive. Worse, the extra privacy built in to Apple and Google’s system means the German institute of public health has no further information on efficacy, because it is unable to collect data about how many users were warned. Following the release of iOS 13.7, the iPhone operating system with the new contact-tracing system, Apple is expected to launch iOS 14 in early October alongside new iPhones. That version of the operating system contains a number of major changes to how iPhones work, including a new privacy-preserving system that allows users to prevent tracking from advertisers. In a blogpost on Wednesday, Facebook warned advertisers that the introduction of the privacy option was likely to lead to “more than 50% drop in publisher revenue”. “Our ability to deliver targeted ads on iOS 14 will be limited,” Facebook said. “As a result, some iOS 14 users may not see any ads from Audience Network, while others may still see ads from us, but they’ll be less relevant.”