I heard there is a newer version of this - batch 4, not sure how it called, probably emerald.
Can you confirm that?
to the best of my knowledge, the manufacturer has never assigned batch numbers to the USB Erupters, that is purely a forums/eBay creation by the members probably for marketing/sales purposes. friedcat has from time to time announced changes such as colors for example and post announcement he would ship those announced "versions". the "versions" were not numeric either. some people confused the Rev 1, rev 2 and rev 3 marking on the PCBs as versions, but the PCBs were made a VERY long time ago... then all the other variations came into existence (heat sink color changes mostly)
I'm not aware of what "batch 4" is, probably someone's conjecture about future "versions" at this point.
If you read through this thread you can see what the future holds for USB miners, as it stands right now.