The Xperia S and Xperia ion were two of the most popular Xperia devices of 2012. The last official firmware for both devices is Android 4.1.2, we don’t expect any future official updates to more updated Android versions. However, you can always rely on the developer community to keep your software relevant. Both devices now have unofficial CyanogenMod 11 (Android 4.4.2) ports.
Both builds are actually quite stable, the Xperia S build has a broken FM radio, no stereo sound and the headphone not working. The Xperia ion build has a bug where the LED notification doesn’t work whilst charging. For more information on the Xperia S click here and for the Xperia ion click here.
The Xperia M has also received an unofficial CyanogenMod 11 (Android 4.4.2) port. Once again, most features appear to be working including GPS. The Xperia M has been stuck on Android 4.1.2, despite the fact that the Xperia M dual has been on Android 4.2.2 for a while. If you’d like to give KitKat a try, check out the XDA thread here.