Share your experience!
Where did u found any info about KitKat for Xperia M?
In Sony Support Center nobody knows about that, is no official info... so it's just rumors which i think never will be reality
Forget about KitKat... 
About the volume bar,set a default theme and restart.It should help.
Resetting default themes does not really "cure" the volume bar bug. It is a bug, and it will reappear each time you restart the phone with a downloaded theme. It's not a big deal, but it should be noted as a bug proper and corrected in the next update. It should not be treated as something which is easily rectified by the user.
/Magnus