T.38 and G.711 pass-through work fine on the MiVB... with a caveat that it is a single, stand-alone system, or the entire call path is vMCD... If there is a physical controller anywhere in the call path, it must have a DSPII card to support T.38. It has supported it for a long time, I remember setting it up with SIP trunks as far back as 2016 or so, and the support was already there, we just never used it.