Yes. Plume supports IPv6, although the implementation depends on the current Networking Mode of your Plume network.
Bridge mode - Plume passes through all IPv6 traffic and configuration between your Wi-Fi devices and your router.
Router mode - If your ISP provides your Plume network with IPv6 address and prefix delegation, then the Plume gateway in router mode will provide dual-stack (IPv4 and IPv6) to your devices.