A US judge has issued a temporary injunction preventing a ban on future downloads of the TikTok app.

The app had faced being blocked from Apple’s App Store and Android’s Google Play marketplace from 23:59 Eastern time.

Existing US-based users would have been able to continue using it.

But they would not have been able to re-download the app if they deleted it from their phones, nor have been offered software updates.

Judge Carl Nichols of the US District Court for the District of Columbia issued a temporary injunction on Sunday evening at the request of TikTok.

The opinion was sealed, meaning that no reason for the decision was released.

TikTok had argued that forcing it off the iOS and Android app stores would have violated the First and Fifth Amendments of the US constitution.

It claimed that preventing some users joining the app unlawfully impinged upon their freedom of speech and that the firm’s own right to due process would have been breached by not giving it a proper opportunity to defend itself first.

“How does it make sense to impose this app store ban tonight when there are negotiations underway that might make it unnecessary?” added a member of the app’s legal team.

The US government’s lawyers in turn had described the app’s parent as being “a mouthpiece” for the Chinese Communist Party (CCP).

The long-term fate of TikTok in the US is still unclear. At present it is owned by a Chinese company, Bytedance, but operated as a separate entity to Douyin – a parallel version used by Chinese consumers.

The Trump administration has claimed Bytedance’s involvement poses a unacceptable national security threat, because it would have to comply with an order to support the CCP’s “malicious collection of American citizens’ personal data”.

To further complicate matters, Beijing has yet to announce whether it will grant Bytedance a licence to include TikTok’s algorithms in any deal.

Algorithms power the app’s recommendation engine, deciding which videos to show to each user, based on the ways they have previously interacted with the product.

The algorithms are highly responsive to each person’s interests, quickly picking up on shifts in behaviour, and are credited with helping make the app so popular.

If China refused to let them be included in a deal, it could scupper any sell-off.

TikTok has said it has more than 100 million active users in the US and about 700 million worldwide.

It has claimed even a temporary ban would threaten its business.

“For TikTok to remain competitive, continued growth at this stage in our development is critical.”

The US government has issued two executive orders targeting TikTok. While the first is designed to prevent it being distributed via Apple and Google, the second is more far-reaching.

March 2012: Bytedance is established in China and launches Neihan Duanzi – an app to help Chinese users share memes

September 2016: Bytedance launches the short-form video app Douyin in China

August 2017: An international version of Douyin is launched under the brand TikTok in some parts of the world, but not the US at this time

November 2017: Bytedance buys lip-synch music app Musical.ly

May 2018: TikTok declared world’s most downloaded non-game iOS app over first three months of the year, by market research firm Sensor Tower

August 2018: Bytedance announces it is shutting down Musical.ly and is moving users over to TikTok

February 2019: TikTok fined in US over Musical.ly’s handling of under-13s’ data

October 2019: Facebook’s Mark Zuckerberg publicly criticises TikTok, accusing it of censoring protests

November 2019: The Committee on Foreign Investment in the United States opens a national security investigation into TikTok

May 2020: TikTok hires Disney executive Kevin Meyer to become the division’s chief executive and chief operating officer of Bytedance

June 2020: India bans TikTok among dozens of other Chinese apps

July 2020: US Secretary of State Mike Pompeo, and then President Trump, say TikTok might be banned

August 2020: Microsoft and Oracle make rival approaches to acquire or otherwise operate TikTok in the US and three other markets. Mr Meyer announces he is leaving the company because the “political environment has sharply changed”

September 2020: TikTok rejects Microsoft’s bid, paving way for Oracle and Walmart to clinch a deal. The US Department of Commerce gives a one-week extension to its original app-store-ban deadline, but there is still confusion over the terms of the arrangement as the time limit approaches

People who test negative for Covid-19 are unable to share the result with the new NHS app for England and Wales if they did not book the test through the app in the first place.

The app asks for a code to register a test result but a code is only received if the test is positive.

Those who enter that they have symptoms without entering a result find a self-isolation countdown begins.

The Department for Health and Social Care said the app would be updated.

People who have been using the app since its launch on Thursday, and who had already booked tests before downloading it, have found that they are unable to stop the self-isolation countdown after reporting symptoms if they then get a negative result, because it does not come with a code they can share.

“That’s so confusing as the app doesn’t tell you that can’t enter negative test booked outside it,” said Prof Deborah Ryan, who originally contacted the BBC.

“And the app still tells you to quarantine if you entered symptoms. So this means I can’t turn off the self-isolation alert in the app?”

The self-isolation alert cannot be de-activated in this situation.

It is not clear how many test results would be affected by this.

The Department of Health said that using the app is “entirely voluntary” and advice to get a test or self-isolate cannot be enforced.

Tests booked via the app will have the results automatically shared with it, it said.

According to the data analyst App Annie the NHS Covid-19 app has been downloaded around 4m times so far.

“By downloading this app you are helping protect yourself and others. If you book your test via the app then the results will be automatically recorded in the app and the isolation countdown will be updated,” said a DHSC spokesman.

People living in England and Wales are being urged to download the government’s official contact-tracing app following its official release.

NHS Covid-19 instructs users to self-isolate for 14 days if it detects they were nearby someone who has the virus.

It also has a check-in scanner to alert owners if a venue they have visited is found to be an outbreak hotspot.

Anyone over the age of 16 is being asked to install the app onto their smartphone.

That is a change from trials, which were limited to the over-18s.

The move reflects a desire by health chiefs for the software to be used by as many students in further education colleges and universities as possible.

The age limit is in line with the Protect Scotland contact-tracing app. And health chiefs behind Northern Ireland’s StopCOVID NI have said they intend to launch a new version that accepts under-18s later this month.

Health Secretary Matt Hancock said that with coronavirus infection rates rising, the app could help keep people safe.

“I urge everyone who can to download and use the app to protect themselves and their loved ones,” he said.

The government had originally intended to release the app months ago. But problems with the initial design and the addition of extra features meant it was only ready for its final public test in August.

One tech expert who has tracked the initiative acknowledged the team involved had worked hard to address concerns about privacy and transparency, but said wider problems could still limit its impact.

“Not only is the app late to launch, but it will be hindered by the delays in the testing system,” Rachel Coldicutt told the BBC.

“If you don’t have symptoms, will a push notification saying you were near someone a week ago make you and your family self-isolate and spend days hitting refresh on the testing website, trying to find a test?”

Although the app allows users to order a coronavirus test and automatically get the results, the government does not believe it will complicate efforts to meet demand.

The app is available for smartphones only – not tablets, smartwatches or other devices.

The handsets must have Android 6.0 (released in 2015) or iOS 13.5 (released in May 2020) and Bluetooth 4.0 or higher.

And some of the latest Huawei handsets are excluded.

The notification will tell the recipient to go into self-isolation for a fortnight – and trigger the start of the app’s countdown clock.

Even if the recipient has no symptoms or a subsequent negative test result, they must stay at home for the duration.

Unlike when a human contact tracer orders someone to self-isolate, the app keeps the subject’s identity a secret.

Those that have not received such an alert, but fill in the app’s symptoms checker and meet the criteria, will be directed to self-isolate for eight days and be directed to an external website to book a test.

Automated contact tracing is designed to complement the work done by humans by helping to identify encounters with strangers – for example, someone standing close to a user while waiting in a queue outside a shop.

When someone anonymously shares a positive Covid-19 test result via the app, a process developed by Apple and Google makes other users’ smartphones check if they had recently detected the infected person’s handset.

But smartphones were not designed for this purpose and the readings involved are not always accurate. This has led to fears of “false positives” – people being instructed to self-isolate who were never at risk.

However, health chiefs believe a recent change to the calculations involved should help minimise the problem: they now take into account when the virus-carrier was at their most contagious.

The Department of Health has confirmed that users who ignore the app’s self-isolation warning are in theory liable for fines of £1,000 or more.

However, because they do not have to identify themselves, officials acknowledge this will normally be impossible to enforce.

One of the app’s other major features is a scanner to let it keep track of pubs, restaurants, hairdressers and other places the user has visited.

So far, the government says more than 160,000 businesses have downloaded a unique code for their property.

The benefit is that if officials later identify a venue as being at the centre of an outbreak, they can update a database which the phones regularly check for a match.

Users can then be told to self-isolate and/or get tested, depending on the circumstances, without having to revealing their identities.

Other facilities, including postcode-based threat updates and details of the latest guidance, are intended to encourage people to regularly look at the app and change their behaviour.

But a major challenge will be convincing them to download it in the first place:

To encourage adoption in England and Wales, the the major mobile networks have agreed not to deduct data used by the app from subscribers’ monthly allowances.

In addition, the app now supports more languages than the test version – adding Turkish, Arabic, Mandarin, Romanian and soon Polish.

And it now allows users to delete individual venue visits from the app’s “digital diary”. This followed feedback from victims of domestic abuse, whose partners often check their phones.

One change, however, may be less popular.

Those told to go into self-isolation because of a contact-tracing match will not be able to challenge the decision.

It has been a long time coming but England and Wales’ Covid-19 app will launch on Thursday.

It follows in the footsteps of Scotland and Northern Ireland’s own efforts but has more features.

Apple and Google’s automated contact-tracing technology will be used to tell people to self-isolate if their phone detects they were near someone later determined to have the virus.

But there’s more, including:

So while contact-tracing may seem like the headline feature, health chiefs say the primary goal is to change people’s behaviour to make them less likely to catch or transmit the coronavirus.

The app is available for smartphones only – not tablets, smartwatches or other devices.

To get started, go to Android’s Google Play or Apple’s App Store and search for “NHS Covid-19”.

The handsets must have Android 6.0 (released in 2015) or iOS 13.5 (released in May 2020) and Bluetooth 4.0 or higher.

And some of the latest Huawei handsets are excluded.

When two devices running the app are close to each other, they exchange Bluetooth “handshakes” to determine the distance and duration, measured in sessions lasting five minutes.

The measurements are not always accurate – and work continues to improve them – but the logs are used to create a cumulative points score for the set of interactions between two people over the course of a day.

The formula may be tweaked over time.

If the points threshold is met and one of the two owners later shares a positive coronavirus test via the app, then the other will receive an alert.

The notification will tell the recipient to go into self-isolation for a fortnight – and trigger the start of the app’s countdown clock.

But the recipient is not told who triggered the alert.

And the authorities cannot identify either party, although they can track how many people have been told to self-isolate.

Even if the recipient has no symptoms or a subsequent negative test result, they must stay at home for the duration.

But because the app lets users remain anonymous and health chiefs want it to be popular, fines for users should not be an issue.

Unlike when a human contact tracer orders someone to self-isolate, the app keeps the subject’s identity a secret.

Only if they subsequently get in contact – for example to arrange a financial support payment – will their name be registered.

Restaurants, bars and other leisure facilities should display an authorised QR barcode on a poster or digital sign, which the app can scan.

The venue will then be added to the app’s “digital diary” of places the user has visited.

And the user will not need to give their name and address to the venue.

If officials later judge the location to be the centre of an outbreak, they can trigger an alert to users who were there.

And this notification might tell them to use the app’s symptoms checker and/or self-isolate.

When a smartphone owner first uses the app, they are given the option of typing in the first part of their postcode – “M23”, for example.

Typically, thousands of other households will have the same code, so although this causes information to be shared with the authorities, it should not identify individuals.

The user is then given a risk-level for their neighbourhood, at the top of the app’s home screen, and can be sent an alert if it changes.

And in turn, the NHS and local government can collect data about the numbers of app downloads and coronavirus cases in their area, helping them manage the crisis.

Users can report symptoms – and when they started – at any time.

If they suggest infection, the user is told to book a test and that everyone in their household must self-isolate for eight days.

Booking a test involves using an external website, which asks for the user’s name and address.

But these personal details are not shared back to the app.

And a unique code lets users receive their test result via the app as soon as it is ready.

The developers suggest the app should account for less than 5% of a device’s battery use.

But if the phone is set to use a low-power mode, owners should go into their settings to exclude the app so it can continue contact tracing at all times.

And while the app is continually checking for updated data, it should not have a significant impact on people’s allowances.

Apple and Google’s framework will not allow two apps to contact trace simultaneously.

So when users cross the border, they need to open the local app and turn on contact tracing within it.

This will bring up a prompt asking: “Switch app for exposure notifications?”

Doing so, will turn off the one they were using beforehand.

While users are normally encouraged to keep the app active and their phone to hand whenever out of the house, there are exceptions.

To avoid people being told to self-isolate when they were protected, or phones logging each other while in lockers, there is an option to temporarily turn off contact tracing, at the bottom of the home screen.

While the human and automated contact-tracing systems are being deliberately kept separate, they should complement each other.

So, for example, if you were in a supermarket queue, human tracers might find it hard to identify the person next in line but the app would be able to.

Likewise, if you were at a pub where a contagious user was sitting but not using the app, you might still receive an alert via the check-in service.

According to modelling done by the University of Oxford, the app can significantly reduce deaths and hospital admissions if at least 15% of the population use it.

But real-world data on how effective such apps have been in other countries using them is scant.

And so far, they have been offered when the levels of infection have been relatively low, meaning the chance of any user receiving an alert has been slim.

Most people have yet to be convinced to install them too – about a third of the population in Ireland, 22% in Germany and only about 4% in France have done so.

As Covid-19 resurges that may change.

And as health chiefs note, there are other measures of success, including whether those that do download the app regularly open it and then change their behaviour as a result.

Tesla founder Elon Musk has announced technology that he says will make Tesla batteries cheaper and more powerful.

At a live presentation that Mr Musk labelled ‘Battery Day’ he also teased the possibility of a $25,000 (£19,600), fully-autonomous Tesla “in about three years time”.

“This has always been our dream to make an affordable electric car” he said.

But the news didn’t excite investors and $50bn was wiped off its stock market value.

The main announcement was Tesla’s new larger cylindrical cells. It was claimed the new batteries will provide five times more energy, six times more power and 16% greater driving range.

But the technology announced is likely to take years to implement.

Tesla’s approach includes integrating the battery so that it forms part of the structure of the vehicle, thereby reducing the effective weight of the battery.

The speech took place in front of 240 shareholders – each sitting in a Tesla Model 3.

Central to cheaper Teslas are innovations in the way the company designs batteries – radically improving their efficiency.

Professor Stanley Whittingham, a member of the National Academy of Engineering, told the BBC that “tackling all the opportunities is high risk, but high pay-off”.

“Many of us have suggested the same steps are necessary, but Tesla has the investment and will to make it happen. Not sure anyone else is willing to do this,” he said.

Mr Musk also announced that as well as purchasing batteries from Panasonic and LG Chem – Tesla itself would begin to make them.

Speaking to the BBC, Casper Rawles, Head of Price Assessments at Benchmark Mineral Intelligence, said scaling up would be “challenging”

“Even with really experienced car manufacturers, we tend to see a very high scrap rate of production in the first couple of years.”

He also warned that so much of the content of the battery is expensive metals – “You can only reduce the cost down to a point”.

Four consecutive quarters of growth have helped Tesla’s share price soar and it is now the most valuable car company in the world.

This is despite criticisms of Elon Musk that some of his technological advances have been exaggerated.

Tesla’s boss however announced that a ‘beta’ version of the full Autpilot software would be available “in a month or so”.

Musk is no stranger to glitzy and sometimes bizarre public demonstrations.