Theremini Firmware

I still I Haven’t been able to determine the version of my Theremini firmware. I saw one post which said I can find out what the version is by pressing the setup button immediately after turning it on. However that it didn’t work. So I still don’t know how to find the version. Can anyone help?

Hold the setup button and then power it on but keep holding the setup button. The version will display and stop displaying when you release the setup button