Apologize if this has already been resolved but has there been any change to the league format to allow Greyjoy decks? - i.e., Is 1 Kings of the Sea set now considered to be valid for League play in addition to the single Core Set and 1 copy each of 2 chapter packs?

Thanks

The way the leagues are set up, you are free to decide for yourself whether or not a "Core Set" includes Kings of the Sea or not. There really isn't anyone policing adherence to any particular format - and the last update from FFG pretty much gave everyone free reign in modifying the format for the local play group/