A firmware update system capable of executing update processing despite that the combination of versions of firmware components installed in an image processing apparatus is normal. A HDD of the apparatus stores in advance a first version management list indicating versions of the respective firmware components and a representative version for managing the versions of the firmware components. Actual versions of the firmware components are collected. When the actual versions are different from the versions in the first version management list, the actual versions and the representative version are transmitted to a server. The server determines update firmware based on the actual versions and the representative version from second version management lists stored in the server. The firmware components installed in the apparatus are updated using the update firmware provided by the server.