September 28th. You can cash the nearby mooncake coupons collected online, and then exchange them directly with your coupons, or you can discount them to outlets without eating mooncakes. The closing date of Hainan Jianingna Cake Roll Exchange is September 28th (August 13th of the lunar calendar). Please don't miss the exchange time. Haikou International Convention and Exhibition Center (24-hour cake collection point).