I can't translate it but supposedly he will be fighting Mousasi or possibly the winner of Rashad-Lil Nog (i doubt winner of Nog-Rashad will be ready or would accept in that short of time)
fight is official now and confirmed by Ariel Helwani
Here's more from Ariel Helwani:
Gustafsson and Mousasi have verbally agreed to meet on April 6 in Sweden. The event is expected to be dubbed UFC on FUEL TV 9. MMAFighting.com confirmed the story with one source earlier in the week, and Swedish MMA Web site Kimura.se is reporting Gustafsson announced the fight at a gym opening in Sweden on Saturday. This will mark the UFC's second trip to Sweden. UFC on FUEL TV 2, also headlined by Gustafsson, was held in Stockholm, Sweden last April, and the sold-out event was a rousing success. The same report states UFC on FUEL TV 9 will also be held at Stockholm's Ericsson Globe Arena.