Use the Novacura Flow server management tool to do a new Flow server installation, upgrade and apply service packs. The difference between an upgrade and a service pack is that an upgrade is between a minor version like 6.2 to 6.3 and a service pack is always within the minor release like 6.2.3 and 6.2.7.
An upgrade includes new features and corrections and can change the structure of the Flow database. All Flow clients need to be updated to the same version as the Flow server.
A service pack only includes corrections that are suitable for patching. A patch will for example not change the database structure of the internal Flow database.