IPv6 is supported via custom attributes:
Here is an IPv6 setup example of what is working for another customer:
Add this custom attribute: Framed-IPv6-Prefix with := operand
Go To: Radius –> Custom Radius Attributes –> Add Attribute
Then, Go To: Radius –> User Accounts –> Edit Radius User Account –> Radius Attributes (tab) –> Click on Add custom attribute.
Add your IP range value as a custom attribute:
Attribute name = Framed-IPv6-Prefix
Attribute value = 2c0f:f970:1aa0::/48 (Your value should look something like this, this is the IP range)
If this setting is not working, it may be that the devices and IPv6 is not set up correctly within your network.
Please let us know if this is working or not working for you.