mental ray for Maya 2016 SP2 is now available for download here or it is automatically installed by the Autodesk Application Manager.
It ships with mental ray 3.13.1.9 which contains improvements for the BSP2 acceleration structure in certain cases, bug fixes for multi-host rendering and for some framebuffer handling issues. The release notes provide more details.
Several bugs were fixed in the mental ray for Maya translator, notably concerning undo when modifying simple mila_material parameters, satellite rendering issues, and a workflow improvement with regard to the new Create->Lights menu and Environment lights.
Inside mental ray 
Hi!
There is a *big* bug when applying animation to material attributes on mental ray materials (persistent as of 2016 SP3): the animation is completely ignored! :-O
Hey Gabriel, you are right: there is a problem with the new Maya parallel DG evaluation. As workaround, go to the Preferences| Settings| Animation and change the Evaluation Mode to DG. Then, it should work again.
Thanks for reporting!
Julia
you’re welcome and thanks for the workaround!
Hello,
I have same problem. The workaround is ok in the viewport but not for rendering in batch. Any ideas ?
Did you save your preferences (File|Save Preferences) before starting the batch render (assuming you started batch from within maya)?
Many thanks for the answer.
No, I didn’t, I just save from preference window. I tried with your purpose and it’s ok now from maya and from command line.
Thank you.