Google has released its first update to the developer preview of Android M, the update comes in the form of Android M Developer Preview 2.
The second Android M Developer Preview comes with a range of updates over the original version, which includes some new API’s, a rage of fixes for reported issues and much more.
The Developer Preview 2 update includes the up to date M release platform code, and near-final APIs for you to validate your app. To provide more testing support, we have refined the Nexus system images and emulator system images with the Android platform updates. In addition to platform updates, the system images also include Google Play services 7.6.
You can find out full details on everything that is includes in the Android M Developer Preview 2 over at the Android Developers blog at the link below. The update is available as an OTA update to developers with supported devices.
Source Android Developers