47 C.F.R. § 76.1609

Within 60 days following the provision of service to 1,000 subscribers, the operator of each such system shall file a notice to that effect with the Commission, and serve a copy of that notice on every television station that would be entitled to exercise network non-duplication protection or syndicated exclusivity protection against it. After July 31, 2020, in lieu of serving paper copies on stations, the operator shall provide the required copies to stations by electronic delivery in accordance with § 76.1600.