In May there was a video with a train carrying T-64As (and T-90As) in Russia, probably towards a plant that would upgrade and restore them. In any case, today all former D/LPR formations are formally part of the Russian Ground Forces. These are the Russian formations that field T-64BVs, although most of their tanks are T-72B/B3s and T-80BVs.

Interesting fact: when Russia annexed Crimea in March 2014, they captured the tank battalion of the Ukrainian 36th Coastal Defense Brigade. The entire battalion (made up of T-64BVs) was later returned to the UAF, probably to try to clean up the Russian image after the unlawful annexation and settle things with Ukraine. In the following weeks 45ish Mig-29s (if I remember correctly) that were previously deployed in Crimea were also returned to Ukraine.