Great news, by default the TG1/TG789 is already configured to accept IPv6! You shouldn’t need to change anything to enable IPv6, if you’d like to check or you think you might have turned IPv6 off in the past please see below.
Each of the devices on your network should now receive an IPv6 address in addition to the IPv4 address they already receive, if some of your devices don’t receive an IPv6 address first try turning them off and back on. If they still have not received an IPv6 address please reach out the the manufacturer of the device as there may be additional steps to enable IPv6 for the device.
If you’ve followed the steps above and are still stuck, please reach out to support for assistance.