AOS R11.1.2 was released and posted for the NetVanta 1531. R11.1.2 is a maintenance release only. It includes bug fixes found since the release of R11.1.0. It does not include any of the features available in later feature releases. Please reference the for specific details. The NetVanta 1531 series firmware can be downloaded from the firmware landing page link below.
Thanks,
ADTRAN Support