Download the tar.gz file from the download page. Find the tar.gz file you need by selecting a version on the right hand side and clicking the appropriate header for more information on the file in question.
Upload the tar.gz file to the op5 Monitor server, or download it to the server directly through wget, curl or similar.
Login to the op5 Monitor server via ssh as the root user.
Untar the tar.gz file in the root/ folder.
Go to the folder that was extracted from the tar.gz file.
Start the upgrade by executing the following script: ./install.sh