X Products has received a letter approving a Non - NFA Can Cannon upper. They say they will have a parts exchange program going shortly for current owners.
X Products Can Cannon Final Approval notice web page
https://xproducts.com/blog/can-cannon-acquitted-batf-new-can-cannon-design

Final Approval BATF Letter for Can Cannon Link
https://www.xproducts.com/sites/default/files/docs/Final-Approval-BATF-Can-Cannon.pdf