Hillary Clinton formally adopted a more progressive stance on healthcare in a proposal released Saturday, as part of an effort to appease Bernie Sanders and his supporters.

The plan includes a “public option” within ObamaCare, an allowance for people to enroll in Medicare at age 55, and increasing funding for community-based health centers by $40 billion over the next 10 years.

Clinton, the presumptive Democratic presidential nominee, emphasized her goal of eventually providing universal healthcare.

"We have more work to do to finish our long fight to provide universal, quality, affordable health care to everyone in America," she said in a statement. 

"Already, the Affordable Care Act has expanded coverage to 20 million Americans. As president, I will make sure Republicans never succeed in their attempts to strip away their care and that the remaining uninsured should be able to get the affordable coverage they need to stay healthy."

In a press call with reporters Saturday timed to coincide with the plan's release, Sanders applauded the move, calling it an "important step forward."

"I congratulate Secretary Clinton for this extraordinary initiative," he said. "It will save lives, it will ease suffering and it will improve healthcare in America and it will cut healthcare costs."

Sanders is expected to end his presidential campaign and endorse Clinton next week. He refused to concede after the former secretary of State became the presumptive Democratic nominee last month, insisting he would keep his fight up through the Democratic National Convention in late July.

Clinton has made policy moves toward Sanders's positions in recent days, and Sanders has praised the moves, in an apparent prelude to an endorsement.

On Wednesday, Clinton released an education proposal that would eliminate public, in-state college tuition for most families — a significant move toward Sanders, who has called for making all public colleges and universities tuition-free.

Clinton signaled her willingness to lower the Medicare age during the campaign before, saying in May that she would support allowing people who are "55 or 50" to buy in to the program.

She also cosponsored legislation as a senator in 2001 that would have set the age at 55.