A few days back, a small firmware update started to roll for Xperia C5 Ultra Dual and now we are seeing the single SIM variant also get its version. Software build version 29.0.A.1.55 has been released for the E5553 and E5506 Xperia C5 Ultra variants, which compares to previous build version 29.0.A.0.161. You can check PC Companion for the update or download the FTF firmware files below.
DOWNLOAD FTF firmware files
Xperia C5 Ultra (E5553) 29.0.A.1.55 Australia Generic (Android 5.0 Lollipop)
Xperia C5 Ultra (E5506) 29.0.A.1.55 Latin America Generic (Android 5.0 Lollipop)