Here we go again; Mamma Mia: The Movie gets sequel with Mamma Mia: Here we go again

Universal is officially moving along on a sequel to the 2008 hit ”Mamma Mia," with ”The Best Exotic Marigold Hotel" scribe Ol Parker writing and directing the new movie. The studio also dated the film, titled ”Mamma Mia: Here We Go Again!," for July 20, 2018.
The sequel will feature Abba songs not featured in the 2008 movie, ”along with some reprised favorites," according to the studio's announcement.
Via Variety
The first film was pretty good, and I mean that title on its own pretty much justifies the existence of a sequel.
...or you could do something entirely different. Like "We Will Rock You" the Movie. Musical was great, even better than Mamma Mia or Rock of Ages, so why not?
Main cast from the first film is back.
Lily James is playing a younger Donna in the '70s.
Robert Yeoman (Grand Budapest Hotel) is Director of Photography.
There will be some reuse of songs, with the most obvious example being Mamma Mia.
Brosnan will be singing more.