The Xperia Z2, Sony’s flagship smartphone for this half of 2014, is receiving a small over-the-air update. It is still Android 4.4.2 KitKat, but the build has gone from 17.1.A.2.55 to 17.1.A.2.69 with this OTA update. There are some reports that Sony has shipped this build with some Xperia Z2 handsets and those without it will be getting it now. There are not major changes made with this update. It seems like Sony is just using it for bug fixes and performance improvements.
Source: Xperia Blog