Share your experience!
I have already updated my Xperia M Dual device to 15.5.A.1.5 two months before. Today it shows a sytem update available and shows the same version as update...
I've seen this before, it was a server issue.
oh....
Thanku for the fast response 
it is showing for me too. tried connecting it to my pc and companion app is showin the same. trying out the update right now.
could it be just a firmware bug removal update.Will post once phone gets updated
if so why they show same version number.
somebody should do this update..ASAP!