"Ed Solomon (Men in Black) is writing the screenplay, per THR (The Hollywood Reporter)."
"All the new Universal monster movies will be set in the present day."
"While we know that The Mummy is set for June 9, 2017, and that another Universal monster movie will be hitting theaters on March 30, 2018, we don't know which one will claim that spot."
"Johnny Depp is still very much in demand, so it's likely that his availability will affect when The Invisible Man will show up on the big screen. All the films will be connected, with characters interacting with each other across the different installments"
The Invisible Man has an IMDb page, though I wouldn't necessarily trust all the info-- I'm not sure that Johnny's character is named "Claude Rains" EDIT- also, the synopsis says "During WWII, when the nephew of scientist Jack Griffen discovers his uncle's formula for achieving invisibility, British intelligence concocts a way for him to aid the war effort." But the articles have insisted that the movie (and all the monster movies Universal is making) will be set in the present day.
We'll see if it actually comes out in 2018, too...
I also read somewhere (i couldn't remember, but i could check out after) that this movie would be a period piece. Not sure if it's because there details about the movie itself or if it's part of the project, because Universal's revisiting all their monsters and they have a team working behind every project or if it's just an assumption based in the rumors that "The Mummy" will be a period piece too