The IRS had released proposed regulations (REG-136118-15) that explain how the IRS proposes to implement the centralized partnership audit regime adopted as part of the Bipartisan Budget Act of 2015.  The provisions contained in that bill created a new audit arrangement for partnerships which, by default, will have a tax imposed at the end of an audit on the partnership to take into account any adjustments that would have increased partners’ taxes had the items been reported on the original return as is being proposed in the audit.

The new centralized regime takes effect for tax years beginning on or after January 1, 2017, though partnerships under exam for years beginning after November 2, 2015 and before January 1, 2018 may elect to have these provision apply.

While the proposed regulations were made available on January 18, they were later taken back by the IRS before publication in the Federal Register due to the change of administrations on January 20.  Shortly after the inauguration, President Trump issued an order that stopped publication of new regulations pending the new administration’s ability to review the work in progress—a step that has taken place in the past following a change of administrations.

Given the nature of these regulations and the law that demands they be issued, it’s likely that these proposed regulations will be later released either virtually or completely as is.  The real final regulations would come after comments are received on these regulations.  As well, there is likely to be a technical corrections bill passed eventually this year by Congress that will also clarify some of these issues.

A detailed analysis of the "not quite proposed regulations" is available here:

Analysis of Not Quite Proposed Regulations for BBA Partnership Audit Regime