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The NHS Covid-19 app has been submitted to Huawei's app store.

The move will initially mean that users of Huawei's older handsets will be able to download it from the firm's App Gallery as an alternative to the Google Play store.

But it potentially paves the way for the contact-tracing software to come to the Chinese firm's newer handsets too.

Huawei indicated that this might happen as soon as November. But others have stressed there are hurdles to overcome.

The app - which is designed for use in England and Wales - has already been downloaded more than 18 million times from Apple and Google's own stores.

All of Huawei's existing phones are powered by Android.

But models released since mid-2019 - including its - lack access to the Google Play app store as well as a related library of tools known as , among other software from the US tech giant.

This is because of a trade ban imposed by the Trump administration that prevents Google and other American tech firms from working with Huawei.

In the case of most apps this is not a problem.

But Google Play Services provides access to the application programming interface (API) on which NHS Covid-19 and other similar contact-tracing apps rely.

The framework is designed to protect users' privacy while giving the app access to some of iOS and Android's underlying functionality, which they could not otherwise access.

To get round this problem, a spokesman for Huawei said that it had written its own API.

This includes its own process to trigger Bluetooth-based exposure notifications, which flag when two people have been standing too close to each other for too long.

Testing regime

For now, NHS Covid-19's developer, Zuhlke Engineering, has simply submitted the existing app for Huawei to review so it can be installed on older handsets via its own store.

But the Swiss firm would have to do more work to make use of the new API.

In theory, it would be relatively simple to re-engineer the software.

However, a source suggested that there would be a "non-negligible" amount of work involved in putting it through the same testing regime the current iOS and Android builds had already been through.

Nevertheless, Huawei's spokesman said it had been in talks with the NHS Test and Trace team responsible for months, and was hopeful officials would soon sign off on the effort.

He added that once they do, it should only be a matter of weeks before the new version could launch.

The firm is keen for this to happen to avoid its forthcoming Mate 40 Pro handsets launching without access to the service.

The 91�ȱ� has asked the Scottish and Northern Irish authorities if they have any plans to publish their own contact-tracing apps - Protect Scotland and ‎StopCovid NI - to Huawei's platform.