Upgrading to this release requires the FortiNAC License. It is possible, however unlikely, older appliances may not have this specific type of license key installed. In such cases, an error will display during the upgrade. For additional details, see KB article https://community.fortinet.com/t5/FortiNAC/Troubleshooting-Tip-Upgrade-fails-with-license-requirement-error/ta-p/246324

Systems on version 9.1.6 must upgrade to either:

• Higher version of 9.1 (e.g. 9.1.7)

• 9.2.4 or higher

Systems on versions 8.2 or lower must upgrade to 8.3 before upgrading to 8.4 or higher.

High Availibility and FortiNAC Manager Environments: The following are required as of 7.2.2:

Key files containing certificates are installed in all FortiNAC servers. License keys with certificates were introduced on January 1st 2020. Appliances registered after January 1st should have certificates. To confirm, login to the UI of each appliance and review the System Summary Dashboard widget (Certificates = Yes). If there are no certificates, see Importing License Key Certificates in the applicable FortiNAC Manager Guide.

Allowed serial numbers: Due to enhancements in communication between FortiNAC servers, a list of allowed FortiNAC appliance serial numbers must be set. This can be configured prior to upgrade to avoid communication interruption. For instructions, see What's New.

As of FortiNAC versions 9.4.2 & vF7.x, Persistent Agent communication using UDP 4567 is no longer supported.

It is recommended the following be checked prior to upgrade to avoid agent communication disruptions:

• SSL certificates are installed for the Persistent Agent target

• Persistent Agents are running a minimum version of 5.3

For additional details see KB article 251359.

https://community.fortinet.com/t5/FortiNAC/Technical-Note-Agent-communication-using-UDP-4567-no-longer/ta-p/251359