I’m sorry to say this, but without the original Expert project, you’ll never be able to update your HomeServer. The project file stored on the HomeServer is tied to the specific software version, and 4.3 is already quite outdated. You can’t simply copy the project file to a VM running version 4.12 or 4.13, because it needs to be transferred using the matching Expert version for that software.

So there’s no way around it—you’ll need to locate the original project and then update it step by step. The required software versions for each update stage are listed in the Gira documentation. Otherwise, you’d probably have to rebuild the entire project from scratch, which could be very difficult, especially if complex logic or custom configurations were implemented.

You can stick with version 4.3 indefinitely and even virtualize it by backing up the HomeServer’s storage using an imaging tool and converting it into a VMDK file. As far as I recall, version 4.3 should boot as long as the network MAC address is correctly adapted to your original HomeServer, since the more complex validation checks were only introduced in later versions.