Both the President of UT and OU send an official request to join the Southeastern Conference. In a statement both school look to join the SEC starting July 2025.
Letter posted below
Original July 26th:
As expected, the University of Texas has notified the Big 12 conference today that it does not intend to extend its athletic media rights agreement past the 2024-25 school year. The University of Oklahoma has said the same today. Providing that notification is the first step toward joining the Southeastern Conference. The next step will be seeking SEC approval.