David Lagercrantz took over the Millenium series after the death of Stieg Larsson. I am just about to read the first of the continuing series, "The Girl in the Spiders Web". More info to follow. The book was great, a solid continuaance of the Larsson trilogy. I will continue with the next one shortly.
Bibliography:
Millenium Series
The girl in the Spider's Web X
The girl who takes an eye for an eye.
The girl who live twice