Can I download older version of Meta Link?

Hi,

I have three products that were supposed to launch on December 1, and all three are dead in the water, waiting on a fix for the Meta Link v83 bugs. The headset update to v83 did not fix any of my issues on any system, Nvidia or AMD, on any of three PCs I've tested on. I switched headsets, cables, and did full uninstall / reinstall cycle. If I start with a basic Unity app and add the All-In-One SDK, it flat out refuses to work with even the most basic OVRCameraRig setup. I don't know how this isn't plaguing everyone else. 

But I need to ship these products. Is it possible for me to download and use an older version of Meta Link ?

Does Meta have pre-release versions of Meta XR All-in-One SDK ? The official one is still v81. That might be the silver bullet. 

Thank you,

-Chilton