There has been some speculation among the Boston fan community for quite some time now about the status of the band's lineup - specifically the roles of Fran and Anthony Cosmo.

Komit, a member of the Gonna Hitch a Ride forum, who is close source to Tom, has posted that Fran and Anthony are no longer in the band. While there are no details surrounding the departure of the Cosmos (their band Cosmo is about to release their first album in December). It was noted in the discussion that Tom wanted to take Boston back to a five-piece band.

So that leaves the following lineup:
Tom Scholz - Lead Guitar, Keyboard, Organ, etc
Brad Delp - Vocals/Guitar
Gary Pihl - Guitar
Kimberley Dahme - Vocals/Bass
Jeff Neal - Drums

Source: Gonna Hitch a Ride