I will try to find it out with next Sony Camera Event :) I currently own only A7 so I don't have silent shutter mode to use my Hologon lens. Yesterday I got a message (here at Zeissimages) from Kolari Vision, it looks they want to help me to convert my camera again. This could prevent me to buy next camera for a while ;)
Thanks Augustaur and Bajanexile for Yours attention.