Sony Xperia M2 D2303, D2306 has received the Android 4.4.2 Kitkat update and the update is rolled out via OTA with 18.3.C.0.37 as the build number. If you are looking to update Xperia M2 D2303, D2306 to this firmware, then you can follow the procedure below.
How to update Xperia M2 D2303, D2306 to Android 4.4.2 Kitkat 18.3.C.0.37 firmware:
1. Download and install Flashtool on your PC.
2. Download the appropriate firmware file for your device from the below links:
3. Now you need to copy the downloaded firmware file and paste in Flashtool > Firmwares folder.
4. Run Flashtool.exe as administrator on your PC.
5. From the top left corner, locate the small lightening button and select Flashmode.
6. Select the FTF firmware file, which you have copied earlier to the Firmwares folder.
7. Next choose wipe Data, Cache and apps log.
8. Tap OK to prepare the firmware files for flashing.
9. Once the firmware files are loaded, it will ask to connect the device with PC.
10. Now power off Xperia M2 and connect it to PC by pressing and holding the Volume Down key. Now make sure not to release Volume Down key, until the whole flashing process is completed.
11. Once the device is detected, the flashtool will start the flashing process.
12. Once flashing process is completed, just disconnect the device from PC and start using the latest firmware.