There has been expected to improve the management of version compatibility among multiple program modules that cooperatively implement a specified function. There is provided a method for a program module to perform a process instructed from an application program. To do this, the method acquires an execution instruction for a specified process from the application program. The method selects a program module for performing the process instructed for execution from a plurality of versions of program modules for performing the specified process. The method allows the selected program module to perform the specified process.