Under a week ago we knew the PTCRB certified an original build for the Xperia Z2. Today that build comes to fruition as the 23.0.1.A.3.9 firmware is rolling out to the O2 phone carrier network in Germany and we don’t predict it stretching out further. So far all signals are pointing towards this being a carrier-specific roll out only. The new build number raises the software version to Android 4.4.4 KitKat just days after we covered the 23.0.1.A.0.167 build for the Z2 and tablet Z2.

We know Android 4.4.4 comes with a revamped phone dialer, Google security patches including the Open SSL fix, bug fixes and more. Correspondingly, Sony release a bunch of their own minor updates for their native applications and services.  The aforementioned build number that we witness rolling out days ago came with Ultra STAMINA mode, PS4 remote Play, additional headphone settings and connectivity, DSEE HX Walkamn app technology and more.


We cannot confirm whether this iteration is arriving as a notification over the air or if users must log in to their Sony PC Companion accounts and install it that way. OTA’s take several days to reach everyone. You can find out if the build number is waiting for you by stopping over at the Settings > About Phone > Software Update > Check For Updates that way. If you are from Germany and are running the original build we are talking about here please leave a comment and let us know the details.

You should know that we do not expect data loss when installing official software updates from phone carriers or manufacturers. However, data loss happens if we are forced into a factory reset. It’s always a great idea to back up the contacts and market apps using Helium from the Google Play Store. Users can back up the data any way they see fit, as long as they make copies of the phone contacts, pictures, videos, music files and any other sensitive data they don’t want to risk losing.

4.4.4 marks the final stages of the KitKat name. There are no more numbers past this one until we reach Android 5.0 Lollipop. However, it’s possible we see another minor incremental update with a different build number before we have the first Lollipop release.