Sony has come up with the Theme Creator tool that lets users create their own Xperia Themes. Sony has announced that the latest BETA version 0.0.3 of the Theme Creator will let users create themes for the devices that are based on Android Lollipop.
Furthermore, Sony has mentioned that it has added only basic Lollipop support to the Theme Creator tool right now with a limited set of preview screens. Though it sounds to be limited, it should be sufficient to get started with creating the Xperia Themes.
Also, the company has implemented significant bug fixes and performance enhancements to the tool. Sony has published online documents guiding users to install the Theme Creator BETA and working with the same. This documentation will help users to create their theme and verify the same before publishing it on the Google Play Store. You can check out the instructions from the Get Started page.