Google said that it has made the inclusion of its Holo system theme in Android 4.0 (Ice Cream Sandwich) compulsory, in order to address concerns about fragmentation of the platform.

While device manufacturers will still be able to develop customised interfaces, the company said in a blog post that support for Holo (pictured) is “a requirement for devices running Android 4.0 and forward.” This will be needed in order to offer access to the Android Market app store – “if the device has Android Market it will have the Holo themes as they were originally designed.”

Google said that the change will make life easier for developers looking to ensure that their apps look good when used on a specific handset. It noted: “before Android 4.0, the variance in system themes from device to device could make it difficult to design an app with a single predictable look and feel. We set out to improve this situation for the developer community in Ice Cream Sandwich and beyond.”

The company noted that it has “no desire to restrict manufacturers from building their own themed experience across their devices.” This is achieved through the DeviceDefault theme, and developers will also be able to write apps supporting these custom interfaces – should they chose to do so.

Ice Cream Sandwich is intended at least in part to address concerns about fragmentation in the Android ecosystem, by integrating the operating system used by Android-powered smartphones and tablets. Previously, different versions of the platforms had targeted different devices, before any further customisation was made by operators.

So far, the platform has not seen widespread adoption by vendors beyond the flagship Samsung-made Galaxy Nexus device. However, a number of manufacturers are promising ICS upgrades for their latest devices, while many new handsets announced at the GSMA Mobile World Congress next month are also likely to adopt the platform.