https://www.popularmechanics.com/military/aviation/a17045156/air-force-plans-to-retire-b-2s-and-b-1s-in-preparation-for-new-b-21-raider/

Am I missing something? The B-21 will replace the B-1. The B-1 is supersonic. Does this suggest the B-21 will be supersonic as well.

The article says: “A concept image of the Raider released in early 2016 shows a similar design to the B-2, suggesting the new bomber will be an upgraded B-2 design that “allows for the use of mature systems and existing technology,” according to an Air Force statement.”

What does it mean?