Running LibreElec 12.2.0 on a Raspberry pi 4 and set a IPv6 manually (It did add the IPv6 by it self), but i am not able to install addons and addons fail when going online, so im curious on, if i am missing something or is there no only IPv6 support with LibreElec? 
I have disabled IPv4 on LibreElec, to ensure it only uses IPv6.