On the Reykjavik: Stage 1 page it shows how there is going to be an initial group stage, followed by the bracket playoffs, which most of us probably expected.
But it shows how 4 teams will be eliminated by the end of the group stage. These 4 eliminated groups will be placed at 9th-10th place and 11th-12th place. To me, this indicates that there will be a larger single or double group stage similar to this one or this one, with the top 8 advancing into a bracket style playoff and the bottom 2 from each group, or the bottom 4 if there is only one large group, being eliminated.
I also believe there's some credibility to this as vlr.gg has also been able to previously find out and post about info from international tournaments such as the amount of prize money for Berlin last year on their page before that information was released publicly by Riot.