Firmware build number 18.3.C.0.39 was recently released for the Xperia M2 (D2303), this brought no noticeable changes with the Android build remaining on 4.4.2 KitKat.
Judging by the PTCRB website, another minor update with build number 18.3.C.0.40 is on the way. This update is due to hit both the Xperia M2 (D2303, D2306) and Xperia M2 Aqua (D2403, D2406). We’ll let you know once the update hits.
Xperia M2 build number 18.3.C.0.39 released
Xperia M2 build number 18.3.C.0.40 certified by PTCRB