Starting with Cupcake, individual builds are identified with a short build code, e.g. FRF85B.
The first letter is the code name of the release family, e.g. F is Froyo.
The second letter is a branch code that allows Google to identify the exact code branch that the build was made from, and R is by convention the primary release branch.
The next letter and two digits are a date code. The letter counts quarters, with A being Q1 2009. Therefore, F is Q2 2010. The two digits count days within the quarter, so F85 is June 24 2010.
Finally, the last letter identifies individual versions related to the same date code, sequentially starting with A; A is actually implicit and usually omitted for brevity.
The date code is not guaranteed to be the exact date at which a build was made, and it is common that minor variations added to an existing build re-use the same date code as that existing build.
| Code name | Version | API level |
|---|---|---|
| Marshmallow | 6.0 | API level 23 |
| Lollipop | 5.1 | API level 22 |
| Lollipop | 5.0 | API level 21 |
| KitKat | 4.4 - 4.4.4 | API level 19 |
| Jelly Bean | 4.3.x | API level 18 |
| Jelly Bean | 4.2.x | API level 17 |
| Jelly Bean | 4.1.x | API level 16 |
| Ice Cream Sandwich | 4.0.3 - 4.0.4 | API level 15, NDK 8 |
| Ice Cream Sandwich | 4.0.1 - 4.0.2 | API level 14, NDK 7 |
| Honeycomb | 3.2.x | API level 13 |
| Honeycomb | 3.1 | API level 12, NDK 6 |
| Honeycomb | 3.0 | API level 11 |
| Gingerbread | 2.3.3 - 2.3.7 | API level 10 |
| Gingerbread | 2.3 - 2.3.2 | API level 9, NDK 5 |
| Froyo | 2.2.x | API level 8, NDK 4 |
| Eclair | 2.1 | API level 7, NDK 3 |
| Eclair | 2.0.1 | API level 6 |
| Eclair | 2.0 | API level 5 |
| Donut | 1.6 | API level 4, NDK 2 |
| Cupcake | 1.5 | API level 3, NDK 1 |
| (no code name) | 1.1 | API level 2 |
| (no code name) | 1.0 | API level 1 |