Table 7.1 shows the SDK versions, the associated versions of the Android firmware, and the percentage of devices running them as of May 2019.
Table 7.1 Android API levels, firmware versions, and percent of devices in use
| API level | Codename | Device firmware version | % of devices in use |
|---|---|---|---|
| 28 | Pie | 9.0 | 10.4 |
| 27 | Oreo | 8.1 | 15.4 |
| 26 | 8.0 | 12.9 | |
| 25 | Nougat | 7.1 | 7.8 |
| 24 | 7.0 | 11.4 | |
| 23 | Marshmallow | 6.0 | 16.9 |
| 22 | Lollipop | 5.1 | 11.5 |
| 21 | 5.0 | 3.0 | |
| 19 | KitKat | 4.4 | 6.9 |
| 18 | Jelly Bean | 4.3 | 0.5 |
| 17 | 4.2 | 1.5 | |
| 16 | 4.1 | 1.2 | |
| 15 | Ice Cream Sandwich | 4.0.3, 4.0.4 | 0.3 |
| 10 | Gingerbread | 2.3.3 - 2.3.7 | 0.3 |
(Note that versions of Android with less than 0.1 percent distribution are omitted from this table.)
Most “codenamed” releases are followed by incremental releases. For instance, Ice Cream Sandwich was initially released as Android 4.0 (API level 14). It was almost immediately replaced with incremental releases culminating in Android 4.0.3 and 4.0.4 (API level 15).
The percentage of devices using each version changes constantly, of course, but the figures do reveal an important trend: Android devices running older versions are not immediately upgraded or replaced when a newer version is available. As of May 2019, almost 11 percent of devices are still running KitKat or an earlier version. KitKat (Android 4.4) was released in October 2013.
(If you are curious, the data in Table 7.1 is available at developer.android.com/about/dashboards/index.html, where it is periodically updated.)
Why do so many devices still run older versions of Android? Most of it has to do with heavy competition among Android device manufacturers and US carriers. Carriers want features and phones that no other network has. Device manufacturers feel this pressure, too – all of their phones are based on the same OS, but they want to stand out from the competition. The combination of pressures from the market and the carriers means that there is a bewildering array of devices with proprietary, one-off modifications of Android.
A device with a proprietary version of Android is not able to run a new version of Android released by Google. Instead, it must wait for a compatible proprietary upgrade. That upgrade might not be available until months after Google releases its version, if it is ever available. Manufacturers often choose to spend resources on newer devices rather than keeping older ones up to date.