The Xperia M2 Dual has seen build number 18.3.1.B.0.18 certified (versus 18.3.B.0.32 currently). Judging by the change in build number, there is a good chance that these new firmware builds bring Android 4.4.3 or even Android 4.4.4 to these handsets. We’ll confirm once the software starts rolling.
Xperia M2 (D2303, D2306) and Xperia M2 Aqua (D2403, D2406) build number 18.3.1.C.0.21 certified
Xperia M2 build number 18.3.1.A.0.21 certified for D2305 variant
Xperia M2 Dual (D2302) build number 18.3.1.B.0.18 certified
Thanks Henry!