One of the biggest features on iOS that isn't available on Android is iMessage, an instant messaging service that allows users to send information over Wi-Fi, 4G LTE, and other forms of internet access to other iOS or OS X users. Earlier this year, there were been rumors swirling around the possibility of the service coming to Android due to Apple's increased focus on services, "which means opening up certain avenues beyond its own iOS and OS X platforms." Today, Daring Fireball's John Gruber has added fuel to the fire by mentioning that he's "heard from little birdies" that a handful of "detailed mockups" of iMessage for Android have been shared around Apple. MacRumors reports: The user interface of the Android app is said to have gone through numerous designs, from one that looks identical to the version on iOS, to another that has a "pure Material Design," using Google's design language it developed a few years ago. Gruber still thinks iMessage on Android "might happen sooner or later," mainly because of iMessage's new monetized Messages App Store, which could net Apple increased income in its already profitable services category if it translated the app to Android. Apple undoubtedly created mockups for all types of products and services, the vast majority of which never make it to release, and it's unclear exactly how far along the iMessage for Android preliminary designs were at the time of their circulation through Apple, or when exactly that occurred. Still, Gruber notes that while an Android version of iMessage "may never see the light of day," even the existence of such mockups "strongly suggests that there's no 'of course not' to it."