A method and system for updating map data of a navigation system in a vehicle is provided. A first version of map data is stored in a memory device of the navigation system, and a first version of map data and a second more recent version of map data are stored in a memory device of a map server. A first route to a driving destination is determined by the map server on the basis of the first version of the map data. A second route to the driving destination is determined by the map server on the basis of the second more recent version of the map data, and the second version of map data and/or route data, which describe the second route, are transmitted at least partially to the navigation system as a function of the degree of agreement between the first route and the second route.