I extracted some firmwares from ITE Technologies IT9135 Windows driver. There was 3 different firmwares, one for old IT9135AX (ver. 1) and two which seems to be compatible with newer IT9135BX (ver. 2). Windows driver version was 12.10.04. (dated 10/04/2012) - it was the newest driver I was able to find...
dvb-usb-it9135-01.fw - versions: 18.104.22.168 / 22.214.171.124
dvb-usb-it9135-02.fw - versions: 126.96.36.199 / 188.8.131.52
dvb-usb-it9135-02.fw - versions: 184.108.40.206 / 220.127.116.11
dvb-usb-it9135-01.fw firmware seems to be just same old which has been there ages. Each of the dvb-usb-it9135-02.fw were newer, according to version numbers reported by the driver, than the old one around the net (old 18.104.22.168 / 22.214.171.124).
These firmwares are compatible with both Linux AF9035 (dvb_usb_af9035) and IT9135 (dvb_usb_it913x) drivers. AF9035 driver supports IT9135 too.
Feel free to test! Especially I am interested to hear if those new ones behaves differently than older.