Sony has just released the Android Marshmallow official OTA update for two Xperia devices, C4 and C4 Dual. The new Android Marshmallow update for Sony Xperia C4 and C4 Dual is live now and you can now download on your devices. The update is rolling out now, it will take some time to hit your devices.
The new firmware version of Xperia C4 is 27.3.A.0.122 and for the Xperia C4 Dual is 27.3.B.0.122. Please note that the update is available only for Xperia C4 (E5303, E5306) and the Xperia C4 Dual (E5333, E5343). There is no information about the other variants of both devices. Hopefully, other models will surely receive the update within a week.