You might remember that the L preview last year introduced a Do Not Disturb mode to Android, but you don't have that exact feature in Lollipop. By the time it was done, this feature became the somewhat more convoluted Priority/None settings. In the M preview it's called Do Not Disturb again, and the basic functionality is a little simpler.
Late last year, we took an early look at a then-rumored feature that we expected to see in an upcoming build of Android: Multi-window. We've heard rumors and whatnot since then, but no physical implementation had been spotted. Now, Multi-window is a real thing, it's part of M, and you can try it today (if you're willing to mod your device a little bit).
Thanks to Andrew and Josh for the screenshots
It's worth mentioning that this is still very early in its development and is quite buggy. Read More
Lollipop 5.0 introduced sliding heads-up notifications instead of the scrolling status bar ticker that had been used on all Android versions prior. They showed up on top of your current screen for a few seconds, then went back into the notification tray. However, the function still seemed quite unfinished, with notifications blocking everything underneath them unless you completely got rid of them or waited for them to disappear. Lollipop 5.1 made it possible to dismiss notifications with a swipe up, sending them back to the tray so you can check them later. Read More
With Android 4.3, Android implemented the idea of always-on WiFi where, even if you had Wi-Fi toggled off, the device and apps could still scan for WiFi networks to improve the location's accuracy. Along with using network triangulation, it's another way of getting your current position as quickly as possible without having to rely too much on GPS signals.
Android M is taking the idea further, adding Bluetooth scanning to the equation. Under the Location settings on M, you'll find a Scanning option in the menu, where both Wi-Fi and Bluetooth scanning can be toggled on and off. Read More
Bluetooth Low Energy is the current preferred method of communication between multiple accessories and Android devices. I can count 4 objects on my body right now that connect to my phone through BLE, not to mention the various accessories strewn across my desk and in other locations around me. Each of these has its own app on my phone that connects to the device every now and then and retrieves data, which, you can easily guess, has a toll on the battery. Read More
While Android Lollipop added a flashlight toggle into Quick Settings, circumventing most third-party torch apps, the function was only accessible in the notification drop-down and as an on/off switch. If you wanted to use the flashlight with morse code, for signaling, or other patterns, you still had to use a separate application and developers of said apps didn't have any clear API to build their software on. They had to hack together solutions for various phones, relying on whatever way the different OEMs had created to access the camera's flash. Read More
There's a minor change to the way Android M implements the lock screen. Instead of the camera and phone shortcuts, you have camera and voice search. Voice Search is accessed by swiping from the lower left corner where you now have a mic icon.
One of Google's big projects for Android M is battery optimization. It's doing this by implementing a new Doze mode that puts unneeded apps into an ultra low-power state that keeps them from doing too much in the background. While this should all work smoothly on its own, it turns out you can go into the settings and fiddle with things.
Among all the interesting tweaks to Android M, the new Google Now on Tap feature has the potential to be the most revolutionary. We won't know for sure until later, though. Google doesn't plan to make this feature fully functional until Android M is officially released.
Last year's Android L preview changed little between its I/O announcement and Lollipop's November release. This will apparently not be the case with Android M—Google expects to push an OTA update to the developer preview about once per month until M is done.