Kelly West/American-Statesman Mumford & Sons will make their debut appearance at the fest this year.

 Austin City Limits Festival organizers say weekend one of this week’s festival sold out “in record time.” Three day passes to the event, headlined this year by Radiohead, Mumford & Sons, Kendrick  Lamar and Major Lazer, went on sale at 10 a.m. Thursday and were sold out by Friday afternoon. Passes to the second weekend of the festival, Oct. 7-9 in Zilker Park, are still available. Daily lineups and single-day tickets for both weekends of the festival will be out this summer.

For the most part the lineup, including all the 2016 headliners remain the same for both weekends of the festival. There are a few notable differences though. If you missed out on tickets for weekend one, the bad news is you won’t be seeing Chris Stapleton, Kacey Musgraves, Andrew Bird, Blue October or Aluna George. But the good news is Willie Nelson, Anderson Paak and the Free Nationals, Awolnation, Conor Oberst and  Atlas Genius are playing weekend two only.

For the festival’s 15th anniversary, organizers have tweaked the layout hoping to improve sound bleed and create a shadier setting for the park’s popular Austin Kiddie Limits stage.