Sony was among the first manufacturers to reveal its plans to launch Android 4.4 KitKat upgrade for its phones. The first wave of devices includes the Xperia Z, Xperia ZL, Xperia Z Ultra, Xperia Z1 and the Xperia Tablet Z. Now, Sony has hinted in its support pages that the Xperia SP will be getting the update, as well as revealed the devices that are currently "under investigation".
Google has already announced that the 4.4 KitKat is designed to scale and automatically fit on the devices with as little as 512 MB of RAM. So, it's pretty likely that more mid-range Sony phones will be able to make it to Android 4.4.
It's too early to talk about a specific time frame for the software rollout for the Xperia T, TX, V and the ZR. However, the Xperia Z, Xperia ZL, Xperia Z Ultra, Xperia Z1 and the Xperia Tablet Z will be getting the KitKat update by the end of the year.