Sony is delivering on its promise to deliver KitKat to the Xperia E1 and Xperia E1 Dual. The update is rolling out now though there might be delays varying by market and carrier. Go to Check for updates in the About screen of the settings on your phone to see if you're among the first to get it.
The update boasts performance enhancements that stem from Android 4.4 KitKat. Other than that the changes are similar to what the Xperia T2 Ultra got, including a tweaked status bar and quick toggles. The custom Sony apps like the Walkman music player, Stamina Mode and others have been updated too.
Despite Google's changes to KitKat, Sony has enabled moving apps to the external microSD card in case the 4GB of built-in storage starts to run low.
Another change is the inclusion of PlayStation 4 like boot animation and live wallpaper. You can change up the look with Xperia Themes.