There has been a lot of hand wringing in the developer community about fragmentation on Android. Device makers are delivering dozens of unique units with their own screen size and resolution, and Google hasn’t had any way to ensure that phones running Android stay up to date on the latest release of the operating system.

But a new study from Localytics reports the problem may not be quite as bad as imagined. “Across all apps using Localytics, a full 73% of Android usage came from devices running a variant of Android 2.3. While the build, known as ‘Gingerbread’, is not the most recent, from a fragmentation perspective it should be good news to developers that such a large majority of users are running the same Android OS version,” says the study.

In other words, a ton of Android phones may be out of date, but at least they are all left behind together. Localitics is clearly a glass half full kind of company. “Add Android 2.2 ‘Froyo’ to the mix, and the majority becomes even more convincing – 23% of Android user sessions were running some flavor of ‘Froyo’. Between the two, Android developers can be confident that they only need to actively target two Android OS builds in order to achieve 96% compatibility with the Android ecosystem,” the study concludes.

When it comes to screen size, Localytics takes a similar tack, pointing out that Android developers can cover most of the bases by going after the most popular form factors. It’s possible, for example, to lock in more than 75% of the smartphone market with  just two screen resolutions.

For developers interested in quantity, this is probably good news. But for apps more interested in quality, there is still a wide range of devices that need to be accounted for to ensure that customers get the best experience.