Google's next operating system, Android M, is expected to be released by the last quarter of the year, maybe as early as September, since an update on Google Plus revealed that it is already preparing for the upgrade.

In a report, Ecumenical News said that the new operating system for Google is now greatly anticipated by Android users since it has been a year when the Lollipop was launched.

Though Android M still remains a big mystery to all, insiders have revealed that it is known as the "Macadamia Nut Cookie."

It was added in the Ecumenical News report that developers can now access Android M with a Preview 1 and Preview 2 available on the Nexus 5, 6 and 9.

"It can also be downloaded on the following models - the Xperia Z3, Z3 Compact, the Xperia Z3 Tablet Compact, Xperia Z2 Tablet, Xperia Z1, Z1 Compact, the Xperia Z Ultra, the Xperia E3 and M2, the Xperia T2 Ultra and the Xperia T3," added the same report.

In preparation for the coming of the new operating system, Android Police said that there will be an update on Google Plus called V6.1 where "Google is working to make its apps compliant with the new permission model in Android M."

This version reportedly presents a new set of warning messages which will inform users that they have "either declined or disabled certain permissions for Google+." Some of the groups identified in this update are the Camera, Contacts, Location and Storage.

Now that the upcoming Google OS is highly anticipated, Alphr assured users that it will be a completely free upgrade for all Android devices.

"Google provides Android for free because it enables you to use their services better," explained the same report.

The operating system is also believed to come with great features like Android Tap which is "a revamped version of the popular Google Now," new app permissions and Domain URLs.

According to Alphr, Google M has also made volume control options easier to comprehend. Also, a "Do Not Disturb" button has reportedly been included on the drop down menu of Android M.

"Tapping it opens up three options of 'Total silence,' 'Alarms only' and 'Priority only.' As before, you can turn these on for a set amount of time or indefinitely," added the same report.

There will also be a new App Tray which ditches the "four-columned horizontally-scrolling pages of apps." Users can now scroll vertically in their devices and can find appal easily with a search field located on the top.