Hong Kong CNN Business  — 

TikTok isn’t the only Chinese-owned app with an uncertain future in the United States.

Restrictions on WeChat are scheduled to take effect Sunday, according to an executive order signed by President Donald Trump that is intended to prohibit “any transaction that is related to” the app.

Weeks after Trump first threatened to ban Tencent’s popular messaging and payments app, it’s still unclear what his executive order will actually do. US Secretary of Commerce Wilbur Ross still needs to specify what constitutes a “transaction,” as defined by the order.

A ban on any services offered by WeChat could have huge implications for US businesses and individuals that rely on the app to communicate with clients, friends and family in China.

A legal challenge

There is some indication that WeChat users may be able to at least keep using the app’s messaging service.

In response to a legal challenge by the US WeChat Users Alliance, a nonprofit run by users of the app, the US Department of Justice said on Wednesday that regulators won’t penalize people who use WeChat to talk with friends or message with businesses.

The Commerce Secretary “does not intend to take actions that would target persons or groups whose only connection with WeChat is their use or downloading of the app to convey personal or business information between users,” the Justice Department said in notice to the alliance.

Such users “will not be targeted or subject to penalties,” it added.

The WeChat alliance has pushed back on those reassurances, saying in court documents that the Justice Department remains “unable or unwilling to state publicly what ‘any transaction that is related to WeChat’ means or what conduct [the department has] deemed to be subject to criminal prosecution.”

At a court hearing Thursday, a US judge said she is willing to grant a preliminary injunction against the executive order at the alliance’s request because Trump’s order is too vague, according to Bloomberg. The judge has not issued a final decision on the request.

The scope of the ban

There has also been much hand wringing over whether the ban could affect WeChat in China.

The American Chamber of Commerce in Shanghai said that some American companies operating in China have flagged that a US ban could affect their ability to accept payments using WeChat’s platform, because orders placed in China often use global tech systems that pass through the United States.

WeChat’s Chinese parent company Tencent declined to comment for this story. It has previously said that it was seeking clarification of the order and emphasized that the international version of WeChat is separate from the Chinese app, which is known as Weixin.

Analysts and experts have also questioned whether US officials would force Apple (AAPL) to remove WeChat and Weixin from its Chinese app store. Such a move would deal a big blow to Apple (AAPL) and other US companies operating in China, where Weixin has become a daily necessity for hundreds of millions of people who use it to pay for goods, hail rides, order food, pay bills and more.

Wedbush analyst Dan Ives said that it is unlikely the US ban will hit the Apple App Store in China. (Google’s Play Store is banned in China.)

“Despite the noise, based on our recent discussions with contacts within [Washington] we strongly believe the WeChat ban will not negatively impact or disrupt Apple’s iPhone ecosystem within the key China market,” Ives wrote in a note last week.

The stance of Washington officials, however, could be undermined by a change of heart from Trump, said Ker Gibbs, president of the American Chamber of Commerce in Shanghai.

The saga surrounding TikTok indicates that nothing is really final until the president signals he is happy with the situation. The latest deal meant to keep the short-form video app operational in the United States would allow its Chinese parent company, ByteDance, to retain majority ownership. But Trump has indicated that he is opposed to that prospect.

“As the back and forth on TikTok confirms … in this administration only the boss’ word means anything,” said Gibbs.

– Selina Wang contributed to this report.