According to EW:
The sixth and final edition of the show recently wrapped production and will debut Thursday, Oct. 4, with the crew back in Seaside Heights for one last party. The network is also airing a retrospective Jersey Shore special titled “Gym, Tan, Look Back” that will include a first look at the final season.
Before filming began, the cast was informed this might be the show’s final season, but they were not officially told the news until this morning.
The overall sense has been that, creatively, the show has run its course.