Delta has made some modifications to their seat-blocking policy, affecting seating in First Class, as well as travel on some regional jets. The change in policy concerns flying on a DL regional jet with 2x2 seat configuration, and may translate to no longer leaving an empty seat next to you. The modification is a positive for First Class customers, though, who will no longer need to be concerned about sitting next to a stranger, as long as the seat-blocking policy is in effect
https://onemileatatime.com/delta-blocking-seats/#current_delta_seat_blocking_policy
https://onemileatatime.com/delta-blocking-seats/#current_delta_seat_blocking_policy