These days Hewlett Packard only sells two internal print server cards for their printers, the HP Jetdirect 620n and the 635n.
Of these two, the Jetdirect 635n (also known as J7961G) has IPv6 support, and is therefore a suitable candidate to upgrade our Laserjet 4250, who's embedded J7949E doesn't do IPv6.
The box has an IPv6 ready Gold logo. The card itself has chips from Broadcom,