A New Sony Xperia™ Home Launcher has Leaked. It Updates the Stock Home Launcher to version 5.1.S.0.0. Changes includes a New Graphic for the dock at the bottom of the handset, as well as for the App Drawer. It also moves the tray options to the left and includes a Search Bar to the right. We also now get the option to have a maximum of seven home screens, instead of five.
There is also a new way to Install Widgets, Apps, Wallpapers & Themes. This comes up when you long press an empty space on the home screen. When you click to install a new theme, wallpaper etc you will see the options for these at the bottom of the handset. Another subtle change we noticed is a new screen transition when moving from one home screen to the next.
via - Xperia Blog