Using the OTA and desktop update I keep on getting that my phone is up to date.
I looked up the customization number with *#*#7378423#*#* > 'Service info' > 'Software info' > 'Customization Version') and it is 1273-0043_R2A
Using XperiaUpdateChecker.exe and Google I cannot find anything about the customization number.
Based on advice from some users I rootded the phone and changed the Customization Version and still did not get the update.
How do I upgrade to the latest Android 4.3 version?