It can be seen that the infringement of copyright cases is increasing as the society becomes more complex and advanced. During the software copyright dispute, there may be a dispute over whether the software is duplicated and made into upgraded software. In this paper, we intend to propose an analysis method for determining whether to upgrade software. For the software upgrade analysis, a software similarity analysis technique was used. The analysis program covers servers, management programs, and Raspberry PC programs. The first analysis confirms the correspondence between program creation information and content. In addition, it analyzes the similarity of functions and screen composition between the submitted program and the program installed in the field. The second comparative analysis compares and analyzes similarities by operating two programs in the same environment. As a result of comparative analysis, it was confirmed that the operation and configuration screens of the two programs were identical. Thus, minor differences were found in a few files, but it was confirmed that the two programs were mostly made using the same or almost similar source code. Therefore, this program can be judged as an upgrade program.