Thursday marked the deadline for tens of thousands of young immigrants to renew their protection from deportation under the Deferred Action for Childhood Arrivals program, or DACA.

For the nearly 800,000 people protected under the program, it was the last DACA renewal opportunity before the Obama-era program ends in March, following its revocation in early September by President Donald Trump.

"If you didn't submit it, you probably are going to lose your status, and that will leave you undocumented in this country," says immigration attorney Lymari Casta. "I suggest that you consult with an attorney that specializes in these matters as soon as possible."

Casta says advocates and lawyers, herself included, believe the one-month deadline was far too soon, despite efforts from nonprofits and other organizations to spread word of it to the community.

"A lot of people probably will miss it, because they weren't aware of this new deadline," she says.

As of Wednesday, federal immigration officials said they had not received paperwork from more than 40,000 DACA-protected immigrants eligible for renewal.