MILWAUKEE (AP) — Officials organizing Milwaukee’s signature summer music festival are offering ticket refunds for people who haven’t been vaccinated against COVID-19.

Festival officials announced on Tuesday that attendees will have to show proof of vaccination or a negative COVID-19 test to get through the gates. The Milwaukee Journal Sentinel reported Saturday that festival officials announced late Friday that anyone seeking a refund must file a request with their original point of purchase online or at the festival box office by Monday. Processing of refunds could take up to a week.

The festival is set to run on the first three weekends in September.