Sony Mobiles will soon roll out Android Jelly Bean 4.3 and KitKat 4.4 updates on selected Xperia handsets. Their official blog does mention the list of handsets that are entitled for this update.
The Android 4.3 Jelly Bean will be rolled out on Sony Xperia Z, Xperia ZR, Xperia ZL, Xperia SP, Xperia Z1, Xperia Z ultra and Xperia Tablet Z. The update will be rolled out next month and if you own any of these devices you will soon get the update option but it could take some more weeks, probably months as the rollouts happen in a phased manner.
The Android KitKat 4.4 update will be passed on to the Xperia ZL, Xperia Z, Xperia tablet Z, Xperia Z1 and Xperia Z Ultra models. Some of the handsets will get both the 4.3 and the 4.4 options.
For more details check out the sonymobiles blogs.