AOS R11.5.0 was released and posted for the NetVanta 1500/1600 series. There are many new features, enhancements, and bug fixes introduced in this release. Please reference the AOS R11.5.0 Switch Release Notes for specific details. The NetVanta 1500/1600 series firmware can be downloaded from the firmware landing page links for each product below.
Thanks,
Adtran Support