Although we can't confirm, but Android M name appeared on an official I/O schedule but was quickly taken down. There are no details on this front but the schedule for May 28th said Android M “brings power of Android to all kinds of workplaces." There have been speculations that Android M will be called Android Muffin.
Another Android version release shouldn't be a surprise since at the same event last year Google announced Android 5.0 Lollipop. But considering that Lollipop is currently just on 10% of Android devices, this is going to add to the fragmentation on Android. Given the buggy releases of Android Lollipop, it would be better for Google to work out the kinks before releasing another version.
