Software updating system, software updating method, and software updating program

摘要

A user terminal 1 obtains a version information file from a first server 2 when activating its application software. If a version-up of the existing application software is determined necessary on the basis of the version information file, obtains an update compression file corresponding to its own version of software from a second server 3 storing the most up-to-date applications, uncompresses a compressed file so as to overwrite an existing application software therewith, and deletes unnecessary files that are not listed on the version information file.