Proposed are a method and a device for receiving significant update information regarding a specific AP via a management frame in a WLAN system. Specifically, a reception MLD receives a management frame from a transmission MLD via a first link. The reception MLD decodes the management frame. The management frame includes a notification method mode field. If a significant update on a second transmission STA occurs, a value of the notification method mode field is set to 1, and the management frame includes significant update information of the second transmission STA.