I've put up a new master cgminer AntS2 firmware in my cgminer-binaries git of current git cgminer 4.9.1+ modified from the last Bitmain firmware 29-Oct-2014 and including all the changes I did last year https://github.com/kanoi/cgminer-binaries/tree/master/AntS2
whether there is support - Extranonce subscription in the firmware? Thank you.
No and never will be. Not interested in adding another MITM stratum security risk.