The Sony Xperia E1 dual (C2104, C2105) has just seen its first firmware certified by the PTCRB. The C2104 model has seen build number 20.0.B.0.68 certified, which relates to Android 4.3. The phone is expected to launch by the end of Q1 2014, so this certification timing ties in with its likely release next month. Amazon UK has it down for a 10 March release, so look for a launch around then.
Thanks Ben and difwwh!