In Mark Millar's words, "The next two that I think will be moving forward pretty quickly are Starlight and Chrononauts, I think they’ll probably be made at the same time as Kingsman 2, if not even before".
Specifically, "I think Starlight’s screenplay is finished now, it was written by Gary Whitta, he finished the screenplay a couple of weeks back and we’re just moving forward now looking for a director".
As to Chrononauts, "there’s one of the actors already and we’re just looking for the second guy. Those two I think are the most likely to be the next two out, and then we should have another three ready to roll next year as well."
And that's not all.
Mark Millar talks Kingsman 2

Will it happen? If so, when? Millar doesn't seem so invested in the sequel, but he didn't abandon the project yet.
