@Tajdk Test whether the SFP+ is recognized in your router slot.
You can then register the module with www.swisscom.ch/start.
But I have my doubts as to whether native IPV6 will work on the RES Anschluss without any problems.
[https://community.swisscom.ch/t5/Router-Hardware/IPv6-nativ-mit-FritzBox/td-p/711115](https://community.swisscom.ch/t5/Router-Hardware/IPv6- native-with-FritzBox/td-p/711115)