State officials have pushed back the opening date for the seven new stations along the Green Line extension through Somerville into Medford until 2021.

The stations had been slated to start opening next year and to finish opening in 2020.

The delay in turn delays the 4.7-mile extension itself, the region’s biggest planned infrastructure project and one of its most joyously anticipated.

While state officials are still optimistic that the extension will happen, several more hurdles remain, including the need for additional federal funding—which could become particularly problematic after Jan. 20.

Officials expect to pick a new team of contractors for the project late next year, per the Globe’s Nicole Dungca.

Meanwhile, they’ve changed the names of two of the seven stations: the Washington Street stop shall now be called East Somerville, and the Lowell Street one will now be called Magoun Square.