This story was first published in September and has been updated.

(CNN) Will hundreds of thousands of young undocumented immigrants lose protection from deportation?

That decision is up to Congress, the Trump administration says.

Attorney General Jeff Sessions announced in September that the administration was rescinding the Deferred Action for Childhood Arrivals (DACA) program.

Pulling the plug on DACA overturns President Barack Obama's signature immigration policy and could upend the lives of more than 700,000 people.

But the Trump administration gave Congress a window to act before any currently protected individuals lose their ability to work, study and live without fear in the US.

Here's a look at some key questions about the program and its future:

Who's been protected by DACA?

These are undocumented immigrants who were brought to the United States as children, a group often described as Dreamers.

About 690,000 young adults are currently protected under the DACA program and officials are processing more than 34,000 additional first-time applications, according to the latest government figures

To be eligible, applicants had to have arrived in the US before age 16 and have lived there since June 15, 2007. They could not have been older than 30 when the Department of Homeland Security enacted the policy in 2012.

Among the accepted applicants, Mexico is by far the biggest country of origin, followed by El Salvador, Guatemala and Honduras.

What does DACA do for them?

DACA recipients have been able to come out of the shadows and obtain valid driver's licenses, enroll in college and legally secure jobs. They also pay income taxes

The program didn't give them a path to become US citizens or even legal permanent residents -- something immigrant rights advocates have criticized, saying it left people in limbo.

How long does the deferral last?

Under DACA, Dreamers were able to apply to defer deportation and legally reside in the US for two years. After that, they could apply for renewal.

The Trump administration put an end to new DACA applications in September and accepted renewal applications for another month.

Now officials say they aren't accepting any more applications . But they say they'll consider requests from residents of the hurricane-ravaged US Virgin Islands and Puerto Rico on a case-by-case basis.

That means if Congress doesn't act, starting March 6, as many as 983 undocumented people could lose their protected status every day -- nearly 30,000 people a month, on average, for two years -- as DACA recipients' permits start to expire.

So what's the administration planning to do?

The Trump administration says it's phasing out DACA in a way that will provide "minimum disruption."

For current DACA recipients, protections remain in effect -- for now.

According to officials:

• Work permits issued under DACA will be honored until they expire.

• New DACA applications that were received by September 5 and renewal applications received by October 5 will be processed.

What has Trump said about DACA?

JUST WATCHED Trump's twists and turns on DACA Replay More Videos ... MUST WATCH Trump's twists and turns on DACA 02:30

When it comes to talking about Dreamers and DACA, Trump has been all over the map.

He vowed to dismantle the program on the campaign trail, but once he took office he suggested he might take a softer stance.

Even after his administration announced its plans to end the program, Trump seemed to signal a desire for Congress to step in and save it, tweeting: "Does anybody really want to throw out good, educated and accomplished young people who have jobs, some serving in the military? Really!"

The administration is already sending mixed messages about how intensely it's getting behind the list of priorities, and most players on Capitol Hill are taking a wait-and-see approach

Is there any hope now for Dreamers?

But a number of past efforts to protect the Dreamers -- widely seen as the most sympathetic group of undocumented immigrants -- have stalled in Congress, and it's unclear whether a new initiative would be able to gather the momentum it needs to pass.

Why did the Trump administration decide to end DACA?

Over the summer, 10 state attorneys general wrote to the President asking him to end DACA and giving him a September 5 ultimatum.

Their message: Rescind DACA, or get prepared for a legal challenge from us.

The move was praised by groups who advocate for stricter immigration controls, who have long decried DACA as executive overreach and argued that it is akin to providing amnesty for lawbreakers.

Immigrant rights activists had said the attorneys general gave Trump what amounted to a false deadline, calling on the administration to stand its ground and keep the program in place.

But in September, Trump administration officials said their hands were tied. They described the program as unconstitutional and something they could not successfully defend in court.

Why are people called Dreamers?

The term Dreamers comes from the proposed DREAM Act, which offered legal status in return for attending college or joining the military. It was first introduced in 2001. The latest version was voted down in the Senate in December 2010.

But the name stuck. And now that the Trump administration has decided to end DACA, you can expect to hear it coming up again in the halls of Congress.

What information and fees were required for DACA?

DACA applicants had to provide evidence they were living in the United States at the prescribed times, proof of education and confirmation of their identities. They also had to pass background, fingerprint and other checks that look at identifying biological features.

The fee to request consideration of deferred action for childhood arrivals, including employment authorization and biometric services, was $495.

Could this information be used against Dreamers now that the program is ending?

This is something immigrant rights advocates say they're very concerned about and they've vowed to take steps to prevent it from happening.

A Department of Homeland Security official has said all the information provided to the government by DACA applicants will remain in the department's system.

US Citizenship and Immigration Services, which administers the program, will give that information to ICE if requested "where there's a significant law enforcement or national security interest," the official said.

Where do I find out more about DACA?