DTA updates COVIDSafe Bluetooth protocol to fix iOS performance

The government’s COVIDSafe contact tracing app will be updated with a new Bluetooth protocol that promises "near 100 percent" encounter logging on both iOS and Android devices.

The Digital Transformation Agency is set to incorporate the open source protocol, Herald, into the app within days in preparation for the busy Christmas period.

It follows months of collaboration with Apple and Google to improve COVIDSafe’s Bluetooth performance, which has proved problematic when running in the background on iOS.

The Herald protocol, which was developed by VMware researchers, improves encounter logging detection, as well as the frequency of detection, for better identification of potential close contacts.

DTA testing of the app with the new protocol as at November shows a significant improvement in Bluetooth encounter logging, particularly when the app is running in the background on iOS devices.

But documentation indicates that this either requires location services to be enabled in the app or that a nearby Android device be used “as a relay” (though this doesn't work for background to background interactions).

iTnews has contacted the DTA for additional information.

COVIDSafe Bluetooth performance summary results with Herald (Source: DTA)

“Testing of Herald in COVIDSafe has demonstrated a near 100 percent detection of close contacts in the foreground and background across iOS and Android devices,” the DTA said in blog post.

“It will give COVIDSafe an ‘excellent’ rating for encounter detection on iPhone to iPhones, and iPhone to Android digital handshakes.”

An excellent rating is where a Bluetooth encounter is logged between 80 and 100 percent of the time under all phone conditions.

The four types of phone conditions are active to active, active to background unlocked, active to locked, and locked to locked.

Prior to Herald, testing put Bluetooth logging at 25 percent to 50 percent of the time between two locked iOS devices and 50 percent to 80 percent of the time when one of the devices is unlocked.

Android to iOS logging will also improve as a result of Herald, with testing now showing an excellent rating under all phone conditions.

Testing also shows “no substantial change in batter usage” on COVIDSafe, which currently chews through between one and three percent of better every hour depending on the phone’s age.

Government Services Minister Stuart Robert said Australia would be the “first country in the world to adopt the Herald Bluetooth protocol”.

VMware says Herald is different to the protocol adopted by the UK’s National Health Services for its original Covid contact tracing app - which has since been replaced by an app that uses the Google and Apple exposure notification API.

Australia has so far ruled out using the API – which relies on an individual reporting exposure to Covid – to ensure health officials can play a more active role in the contact tracing process.

DTA CEO Randall Brugeaud told senate estimates in October that “there is no intention to jettison the current app and start again, or take an entirely new app from another country or company”.

Robert added that the app's source code has been made available to the tech community for review via Github ahead of its release on the Apple App Store and Google Play Store.

The update of the app coincides with a new advertising campaign to remind the community “not to be complacent in regards to the risks of spreading Covid-19”, Health Minister Greg Hunt said.

“The latest advertising campaign, which begins this week, is an important reminder that as we head into Christmas and restrictions are easing, people should maintain Covid-safe behaviours,” he said.

Around 7.1 million Australians are said to have downloaded and registered the COVIDSafe app since it was launched in late April, though whether the app remains on their phone is an open questions.

In NSW, the app has been used to identity 17 that weren’t identified by manual contract tracing, as well as a further 63 that were picked up in the manual tracing process.