Sony has begun rolling out Android 5.1 for the Xperia C4 smartphone users through an over-the-air update that bumps the current build version of the phone to 27.2.A.0.155. Along with the C4, its dual SIM model is also receiving the update but with a slightly different build number, that is, 27.2.B.0.155.
Five of the six variants of the Xperia C4 as well as the C4 Dual have received the update so far, except the E5343. Even users of C5 Ultra are in for some good news. A similar update is seeding for both the C5 Ultra and the C5 Ultra Dual.
The OTA for C5 Ultra models, including E5503 and E5506, brings build 29.1.A.0.87, whereas the C5 Ultra Dual variants such as E5533 and E5563 are getting build 29.1.B.0.87. The FTF links are yet to become available using which you can install the stock firmware manually on your phone through the Sony flashtool, reports Xperiablog.
To check the availability of the update on your phone manually head over to Settings>> About phone>> Software update. The official software support pages for both the Xperia C4 and the C5 Ultra include all the latest bug fixes and system improvements. The pages further note that the next version is Android 6.0. The release is quite surprising, as the above Xperia C series devices and a few other Xperia handsets were expected to skip Android 5.1 and update directly to Marshmallow.