From the NAPUS Political and Legislative Bulletin:
As early as next week, the Sen-ate may bring S. 1789, the Lieberman-Collins-Carper-Brown postal bill to the floor. In November, the Senate Homeland Security and Governmental Affairs Committee approved the legislation by a 9-1 vote. The Committee has yet to file a report on the bill and the Congressional Budget Office has not released its cost estimate. However, such documents may be filed imminently.
As reported previously in this Bulletin and the Postmasters Gazette, there are at least 4 postal bills that could be considered by the Senate. While it is doubtful that the bills would be proposed as substitutes for S. 1789, it is likely the bills could be disassembled, and parts of the bills may be proposed as amendments to S. 1789.