Hi @Ian_Clark,
There’s a ticket with development addressing compatibility with Starlink WANIPv6 addresses. When an update is available it will be posted here: ARC With Starlink: IPv6 WAN IP Issue with RoonServer [Ticket In] and in the Release Notes of the Early Access section where we test changes.
Starlink issues all IPv6-capable routers (including Starlink routers) a native IPv6 address, but Starlink also issues IPv4 addresses behind their CG-NAT. This will depend on your geography and tier of service. You can read here for more info: IP Addresses.
Please take note that once we implement the fix, you’ll need a native IPv6 or properly prefixed dual stack setup for RoonServer and ARC to retain line of sight. CG-NAT will break ARC in any IPv4 implementation.