Android 4.0 Requires Holo Theme to Be Available On All Phones
Google today indicated via the Android Developers Blog that all Android 4.0 devices, be they smartphones or tablets, must include the native Android 4.0 Ice Cream Sandwich "Holo" theme for app compatibility. According to Google, any device that has access to the Android Market has to include the Holo theme. The standardization applies to the Holo widgets too, which Google wants to be consistent from device to device. Google said that the intent behind this decision is not to limit what developers can do with respect to the appearance of their apps, but rather to provide a level of consistency in how developers can create apps that will run on all devices. Google has made a new API (Level 14) available for developers to work with the themes and incorporate them into their applications moving forward. Google also offers details on how to make apps designed for Android 4.0+ work with devices running Android 2.3 and lower.
That's a start--