1. In combination: a computer-based navigation system including a processor and a navigation application program run on the processor, said navigation application program including programming code to provide navigation features including use of a geographic database stored on a medium, wherein said navigation application program is at a first version level, an improvement comprising: at least one replacement routine, wherein said replacement routine is at a second version level, wherein said second version level is later than said first version level, and wherein said at least one replacement routine at said second version level is called by said navigation application program at said first version level and executed to use an updated geographic database stored on an updated medium to perform part of said features of said navigation application program.