According to a Sony Representative, he said that our phone [ Xperia SP ] won't be receiving the much awaited "KitKat" Update
you can check it out for yourself right here
Note: That translates to "I got confirmation from Sony that the Xperia SP won't be receiving the Kitkat update"
This is one of the reasons why I am getting the Z1c I mean Sony always forgets the Non-Flagship phones
I mean look the Galaxy Nexus has a KitKat Update!!! and ours doesn't?