“We’re having some trepidation,” said Judy Solomon, vice president for health policy at the liberal Center for Budget and Policy Priorities. “This is going to be another new thing just like the roll out of HealthCare.gov.”

Last month, the Obama administration released drafts of the forms employers and individuals will have to fill out. But those leave unanswered many questions about how it’ll all work. The details are expected to be included in “practical” instructions the agency plans to release later this month that will detail how to complete the new forms, the IRS said.

At this point, the new forms look “very daunting” for taxpayers, said Mark Ciaramitaro, vice president of health care services at H&R Block. “Overall, we expect the complexity level is just going to go up for a significant group of moderate- to low-income people, whether they got insurance through the marketplace or they didn’t.”