A method and a system for updating software containing a first program and a first data group. The first program has a corresponding first program version number and the first data group has a corresponding first data group version number. The method includes providing a second program which has a corresponding second program version number; updating the first program using the second program when the value of the first program version number is different from the value of the second program version number; and deciding whether to update the first data group or not according to the updated first program version number of the updated first program.