Though Android N is nearing release, adoption of its predecessor is still slow-going.
According to this month's Android developer stats, only 7.5 percent of Android devices are running Marshmallow. The mobile OS lags behind Jelly Bean (20.1 percent), KitKat (32.5 percent), and Lollipop (35.6 percent). Froyo, Gingerbread, and Ice Cream Sandwich, meanwhile, still carry a combined 4.3 percent.
Last September, Lollipop had 21 percent market share ahead of Marshmallow's release. Android N will likely make its debut around the same time this year, though we'll learn more at Google's I/O developer conference later this month.
The open-source nature of Android means that it's extremely popular around the globe. But unlike Apple, which controls the release of new mobile OSes itself, Android updates are largely handled by mobile carriers, with the exception of Google Nexus devices. As a result, it can take awhile for phones to get updated (if at all), so many of the phones running Marshmallow are new devices that come pre-loaded with the OS.
Developers got a welcome surprise in March when Google rolled out early access to Android N, which included things like a multi-window feature and overhauled notifications. A second iteration of the Android N Developer Preview arrived last month, fixing a number of bugs, and adding launcher shortcuts, API changes, and Emoji Unicode 9.
For more, see PCMag's review of Google Android 6.0 Marshmallow, as well as our preview of Google Android 7.0 N.