Simply run the setup.exe for the new version over the top of the existing installation.
It will detect that an older version is already installed and prompt you to upgrade the existing installation to the newer version.
If the schema has changed between the DBmarlin version you are moving from and to then data migration will be required which could take some time and you will see a message like this.
Data migration could take several minutes or even several hours for large databases. During this time you will not be able to start any sensors until the migration has completed. Please do not terminate the process or stop postgres during this time or you will end up with an inconsistent database.