Burger King is upgrading its Whopper with a better bun, improved mayo, and a new box to fix sogginess, aiming to boost satisfaction.

Burger King is updating its Whopper for the first time in nearly a decade, introducing a premium bun, creamier mayonnaise with citrus and sweet notes, and a clamshell box to prevent sogginess and improve presentation. The beef patty remains unchanged, and the upgrades, developed after seven months of testing, aim to address long-standing complaints about the burger falling apart. The changes are being rolled out across more than 7,000 U.S. locations, with franchisees facing an additional $4,000 annual cost—though Burger King urges them not to pass it to customers. The move follows a period of declining customer satisfaction and a 3.2% rise in U.S. same-store sales, with President Tom Curtis personally gathering feedback to guide improvements.