Genesis Digital Lens Latest Version

Can anyone tell me what is the latest eprom version of the Genesis digital lens that was produced.
Do you know what serial number that started the production of this latest version?
Is there a sonic difference between the versions?
Thank you for any help!
The below is a note I kept from my previous reading:

"If you bought a Lens with serial number lower than 111209, it has the old output driver" (from Sterophile review) - the new ouput driver is apparently much superior.
Thank you for your responses! It's seems a though there are updated eproms such as V2.2 to V2.6 versions. Is anyone familiar with the differences between the two and the sonic improvements if any.
Thank you!