First and foremost, the writing staff has decided to ignore parts of the series finale back in 1997. That means that the Conner family never won the $108 million Illinois state lottery. So far, pictures from set reveal that the family home is more or less an exact replica of the original.
Perhaps even more importantly, the revival is ignoring the death of Dan Conner in the original series. John Goodman will return, though it's unclear if the new season will completely ignore his heart attack or rewrite it as if he survived. Other sitcom revivals have taken this route lately, notably Will & Grace.
Another contentious point among Roseanne diehards the return of Becky, the oldest Conner daughter. Showrunners have confirmed that Lecy Goranson, the original Becky, will reprise her role. Sarah Chalke, who filled in as Becky throughout the later seasons, will return as well, this time in a different role. ABC has yet to reveal what her new role will be.
John Galecki will also return to the series, despite his other engagements. At first, fans thought it might be too much to hope that the Big Bang Theory star would make time to reprise his role as Darlene's husband David. However, Galecki posted a picture from set on Instagram earlier this month, confirming that he'll at least make an appearance.
Becky's husband Mark, however, may not be rejoining the rest of the characters. Glenn Quinn, who played Mark in the original series, passed away in 2002 after a drug overdose. Early looks have revealed that Darlene and David have an 8-year-old son in the revival season named Mark, presumably in honor of Becky's husband. To many fans, this is a sign that the producers aren't looking to replace Quinn.
So far, there haven't been too many revelations about new characters, though we do know that Emma Kenney from Shameless has been cast as Harris, David and Darlene’s 14-year-old daughter. Jayden Rey will join the cast as D.J.’s daughter, and Ames McNamara will play 8-year-old Mark.
As for the episode count, that seems to be a flexible number. At first, ABC announced eight new episodes of Roseanne. They added one more episode to the order in November, bringing season 10 up to nine episodes total. A recent Instagram post by Barr confirmed that the original theme song will return along with the show.