Here are the model numbers of Samsung S4 Variants that were recently released(in November 2013) in China market, which Rajan ji is talking about. All of these three variants support both Band 3 & Band 40.
Samsung GT-i9508C TD-SCDMA2000, TD-SCDMA1900, LTE1800 (B3), LTE2600 (B7), TD-LTE2600 (B38), TD-LTE2300 (B40), TD-LTE1900 (B39) Samsung GT-i9508V TD-SCDMA2000, TD-SCDMA1900, LTE1800 (B3), LTE2600 (B7), TD-LTE2600 (B38), TD-LTE2300 (B40), TD-LTE1900 (B39)