By Tami Luhby and Katie Lobosco, CNN

(CNN) -- The Senate is negotiating how much to adjust the Democrats' massive coronavirus relief package that passed the House last week.

While the final Senate bill has not been released yet, lawmakers are expected to make two major changes -- narrowing eligibility for the stimulus checks and nixing an increase in the federal minimum wage to $15 an hour.

The bulk of the Senate legislation will, however, largely mirror the $1.9 trillion package approved by the House and laid out by President Joe Biden in January. Once the chamber passes its version of the bill, it goes back to the House for a vote and then onto the White House for Biden's signature.

Senate Democratic leaders are facing more hurdles to advancing the legislation since the party can't afford to lose a single member thanks to the 50-50 split in the chamber. Plus, they must adhere to the strict rules of reconciliation, which they are using to approve the bill without any Republican support.

Time is of the essence. An estimated 11.4 million workers will lose their unemployment benefits between mid-March and mid-April unless Congress passes its next coronavirus relief package quickly, a recent study by The Century Foundation found.

Here's what's we know so far about what's in the Senate bill:

Stimulus checks

The Senate is expected to amend the House bill on the $1,400-per-person stimulus payments to tighten eligibility.

Individuals earning less than $75,000 a year and married couples earning less than $150,000 will receive $1,400 per person, including children. That will get money to about 90% of households.

The checks will phase out faster than previous rounds, completely cutting off individuals who earn more than $80,000 a year and married couples earning more than $160,000 -- regardless of how many children they have.

The bill passed by the House set the income caps at $200,000 for couples and $100,000 for individuals. The Senate change leaves out about 7 million families, according to an estimate from the Penn Wharton Budget Model.

Unlike the previous two rounds, adult dependents -- including college students -- are expected to be eligible for the payments

Unemployment assistance

Some senators were looking to make some changes to the House bill, including reducing the federal boost to unemployment benefits to $300 a week and extending the duration of pandemic jobless programs by another month. But these efforts have not progressed.

The House bill calls for extending two key pandemic unemployment programs through August 29. It would also increase the federal weekly boost to $400, from the current $300, and continue it for the same time period.

It would lengthen the duration of the Pandemic Unemployment Assistance program to up to 74 weeks, from 50 weeks, and the Pandemic Emergency Unemployment Compensation program to 48 weeks, from 24 weeks.

The former provides benefits to freelancers, gig workers, independent contractors and certain people affected by the pandemic, while the latter increases the duration of payments for those in the traditional state unemployment system.

The President's plan had called for continuing the benefits through the end of September.

Out-of-work Americans will start running out of Pandemic Unemployment Assistance and Pandemic Emergency Unemployment Compensation benefits in mid-March, when provisions in December's $900 billion relief package begin phasing out.

The $300 enhancement also ends in mid-March.

Minimum wage

The Senate bill will not include an increase in the federal minimum wage, which House Democrats proposed raising to $15 an hour.

The parliamentarian ruled in late February that increasing the hourly threshold does not meet a strict set of guidelines needed to move forward in the reconciliation process, which would allow Senate Democrats to pass the relief bill with a simple majority and no Republican votes.

The House legislation would increase the federal minimum wage to $15 an hour by 2025 in stages. It would also guarantee that tipped workers, youth workers and workers with disabilities are paid the full federal minimum wage.

Aid to states

The legislation would provide $350 billion to state and local governments, as well as tribes and territories.

States and the District of Columbia would receive $195.3 billion, while local governments would be sent $130.2 billion to be divided evenly between cities and counties. Tribes would get $20 billion and territories $4.5 billion.

The Senate version of the bill slightly revises the formula to help states with smaller populations and boost the minimum they will receive.

Additional assistance to states has been among the most controversial elements of the congressional rescue packages, with Democrats looking to add to the $150 billion in the March legislation and Republicans resisting such efforts. The December package ultimately dropped an initial call to include $160 billion.

Here's what else was in the House bill

Nutrition assistance

The House plan would extend the 15% increase in food stamp benefits through September, instead of having it expire at the end of June.

It also contains $880 million for the Special Supplemental Nutrition Program for Women, Infants, and Children, known as WIC, to help increase participation and temporarily improve benefits, among other measures. Biden called for investing $3 billion in the program.

And it would allow states to continue the Pandemic-EBT, which provides families whose children's schools are closed with funding to replace free- and reduced-price meals the kids would have received, through the summer.

Housing aid

The legislation would send roughly $19.1 billion to state and local governments to help low-income households cover back rent, rent assistance and utility bills.

About $10 billion would be authorized to help struggling homeowners pay their mortgages, utilities and property taxes.

It would provide another $5 billion to help states and localities assist those at risk of experiencing homelessness.

Tax credits for families and workers

The legislation beefs up tax credits for families and certain low-income workers for 2021.

In an effort to combat poverty, it would expand the child tax credit to $3,600 for each child under 6 and $3,000 for each child under age 18. Currently, qualifying families can receive a credit of up to $2,000 per child under age 17.

The credit would also become fully refundable so more low-income parents could take advantage of it. Plus, families could receive payments monthly, rather than a lump sum once a year, which would make it easier for them to pay the bills.

The bill also enhances the earned income tax credit for workers without children by nearly tripling the maximum credit and extending eligibility to more people. The minimum age to claim the childless credit would be reduced to 19, from 25, and the upper age limit would be eliminated.

This would be the largest expansion to earned income tax credit since 2009.

Optional paid sick and family leave

Unlike Biden's proposal, the House bill would not reinstate mandatory paid family and sick leave approved in a previous Covid relief package. But it does continue to provide tax credits to employers who voluntarily choose to offer the benefit through October 1.

Last year, Congress guaranteed many workers two weeks pay if they contracted Covid or were quarantining. It also provided an additional 10 weeks of paid family leave to those who were staying home with kids whose schools were closed. Those benefits expired in December.

Education and child care

The bill would provide nearly $130 billion to K-12 schools to help students return to the classroom. Schools would be allowed to use the money to update their ventilation systems, reduce class sizes to help implement social distancing, buy personal protective equipment and hire support staff. It would require that schools use at least 20% of the money to address learning loss by providing extended days or summer school, for example.

The money is also intended to help prevent teacher layoffs next year when some states may be struggling to balance their budgets. The pot of money will remain available through September 2023.

The Democratic bill is in line with what Biden proposed, but calls for more than six times the amount of funding for K-12 schools than a compromise plan offered by a small group of Republican senators.

The House bill now includes nearly $40 billion for colleges. Institutions would be required to spend at least half the money to provide emergency financial aid grants to students.

Altogether, $170 billion would be authorized for K-12 schools and higher education. Last year, Congress approved a total $112 billion between two relief packages that went to K-12 schools and colleges.

The bill would also provide $39 billion to child care providers. The amount a provider receives would be based on operating expenses and is available to pay employees and rent, help families struggling to pay the cost, and purchase personal protective equipment and other supplies.

Health insurance subsidies and Medicaid

The bill would make federal premium subsidies for Affordable Care Act policies more generous and would eliminate the maximum income cap for two years.

Enrollees would pay no more than 8.5% of their income towards coverage, down from nearly 10% now. Also, those earning more than the current cap of 400% of the federal poverty level -- about $51,000 for an individual and $104,800 for a family of four in 2021 -- would become eligible for help.

In addition, the legislation would bolster subsidies for lower-income enrollees, eliminating their premiums completely, and would do the same for those collecting unemployment benefits in 2021.

The bill would also provide assistance for those who want to remain on their employer health insurance plans through COBRA. These laid-off workers would pay only 15% of the premium through the end of September, though that can still prove costly.

Also, the legislation seeks to entice states that have yet to expand Medicaid to low-income adults to do so by boosting their federal Medicaid matching funds by 5 percentage points for two years.

More money for small businesses

The bill would provide $15 billion to the Emergency Injury Disaster Loan program, which provides long-term, low-interest loans from the Small Business Administration. Severely impacted small businesses with fewer than 10 workers will be given priority for some of the money.

It also provides $25 billion for a new grant program specifically for bars and restaurants. Eligible businesses may receive up to $10 million and can use the money for a variety of expenses, including payroll, mortgage and rent, utilities and food and beverages.

The Paycheck Protection Program, which is currently taking applications for second-round loans, would get an additional $7 billion and the bill would make more non-profit organizations eligible.

Another $175 million would be used for outreach and promotion, creating a Community Navigator Program to help target eligible businesses.

Vaccines and testing

The House bill provides $14 billion to research, develop, distribute, administer and strengthen confidence in vaccines. It would also put $46 billion towards testing, contact tracing and mitigation, including investing in laboratory capacity, community-based testing sites and mobile testing units, particularly in medically underserved areas.

It would also allocate $7.6 billion to hire 100,000 public health workers to support coronavirus response.

The legislation also provides $50 billion to the Federal Emergency Management Agency, with some of the funds going toward expanding vaccination efforts.

The President's plan called for investing $20 billion in a national vaccination program.