Spaceflightinc is suppose to announce / confirm the launch. Not sure why they are so slow. Then only will Kleos and all other rideshare partners inform the public.The launch hazard area for the Transporter-2 mission is now published on Patrick Air Force Base, Cape Canaveral. The launch is scheduled for 25 June at 21 at 12:45 PM - 4:45 PM. If launch is delayed the next attempt will be 26 Jun 21.
https://www.patrick.spaceforce.mil/
I would think this is a credible source...