Milestone replied, pointing to detailed upgrade instructions starting on page 53 of the Administrator manual.
Specific to your scenario, Milestone highlighted the following:
Perform the upgrade in this order:
- Upgrade the management server with the Distributed option in the installer.
- On the wizard page where you choose components, all management servers components are preselected.
- Specify your SQL server, and choose to keep the database.
Note: When you start the installation you lose failover server functionality (while management server is being installed).
- Upgrade failover servers. From your management server's download web page (controlled by the Download Manager), install the Recording Server.
Note: At this point the failover server functionality works again.
- Upgrade the recording servers. You can install recording servers using the installation wizard (see "Install the recording server" on page 36) or silently (see "Install a recording server silently" on page 37). The advantage of a silent install is that you can do it remotely.
- Upgrade the event server
Milestone also noted:
Furthermore, we can always upgrade from any old version of XProtect Corporate / Expert to the newest version in one go. You never need to do it stepwise.
The new XProtect Smart client will also always be compatible with the last 2 major releases (or 2 years with the new 3 months release interval) So should the customer have multiple systems or sites the new clients can be used for all sites (unless very old)
The video recordings and the system settings will always be retained.