A quick heads-up to let T-Mobile Xperia Z (C6606, C6616) owners know that a new firmware build has been certified on the PTCRB website. Firmware version 10.3.1.E.0.191 uses a different template to the previous version i.e. 10.3.1.E.0.XXX versus 10.3.1.A.X.XX – what relevance this has, we can’t say right now.
We don’t think the ‘E’ would signify an Android 4.3 build, we may not even see this build released (it hasn’t appeared for the HSPA+ and European LTE models). We’ll keep you posted, Sony has promised details on the progress of the next major Android updates later this week.