Those users with Nexus devices are in for a change soon: Google has started officially rolling out its new mobile OS, Android 6.0, to many of its Nexus phones, including the Nexus 5, Nexus 6, the 2013 Nexus 7 and Nexus 9, as well as to the Nexus Player.

Last week, a list of devices eventually slated for Marshmallow came out, but it makes sense that Google started with its own line of Nexus smartphones. However, Marshmallow will soon also become available to many Samsung phones, as well as Motorola devices.

Google promises a smooth transition from its previous OS, Lollipop, and Marshmallow. Nexus users with compatible devices will get the update over the air, meaning that there's no need to plug the device into a computer to download the update. Instead, a notification that Marshmallow is available should come up on the device, with the option of updating it then and there, complete with installation instructions.

Marshmallow brings a variety of updates to the Android OS, including superior battery optimization over previous versions. Marshmallow has a feature called Doze that helps Android know when to disable processes on devices once they've been idle for a certain period of time. There is also an app standby feature that limits how seldom-used apps impact a phone's battery life.

Marshmallow also brings support for fingerprint scanning, something that's become a growing security trend in the smartphone industry. Users will also be able to take advantage of USB Type C, as well as set specific permissions for apps on a case-by-case basis.

The new Android OS will also introduce Now on Tap, which means that by holding the home button, users can get help with something via Google Now without leaving the app or website they currently have open.

"Now on Tap anticipates what you need in the moment," writes Google on its official Android OS website. "With a simple tap, you can get cards with useful information and apps that feed your need to know."

Even the app menu gets an overhaul in Android 6.0 and looks something more like what one might see on Windows 10 devices–no more flicking through page after page of apps: instead, the list of apps stays on one page and the user scrolls down.

Note that Google's Nexus 5X, Nexus 6P and the Google Pixel C already come with Marshmallow installed.