Soon after taking the wraps off the new Android M at the ongoing I/O developer Conference, Google released the Android M Preview SDK for the developers, so that they can begin making their applications ready for the final Android M release in Q3 this year.
The search giant has also published the Android M preview factory images for Nexus 6, Nexus 5, Nexus 9 and Nexus Player devices, so the developers can even test their apps on a live device.
Unlike Android L preview, Android M preview will be getting monthly over-the-air updates with new changes and features. Meaning, you can expect to see at least two updates before the final release. This will help a lot in keeping the preview devices up-to-date.
You can head over the Android M preview microsite to grab the necessary downloads. The instructions are available on the website.