HALB appliances do not support up in-place upgrade unlike other Parallels RAS components.
You need to replace the old appliance with a new one preserving its network settings.
Please follow the steps below to perform the upgrade:
1. Take a note of the current HALB configuration - IP address, subnet mask, Default Gateway, DNS servers and so on:
2. Go to the Parallels RAS download link and download the HALB appliance in the appropriate format;
3. Import it to your hypervisor and assign it to the same network as the old appliance;
4. Go to RAS Console → Farm → HALB → Devices and remove the old appliance:
5. Shutdown the old appliance;
6. Configure the new appliance using the settings from step 1;
7. Add the new appliance to RAS Console and click Apply;
8. Remove the old appliance from the hypervisor.