Google announced 12L at Android Dev Summit on 27 October 2021 and released Developer Preview 1 the same day. It was for developers only, and it ran only in the Android Emulator: phones did not get it.
| Release date | 27 October 2021 |
| Build | SPP4.211001.003 |
| Security patch | October 2021 |
| Devices | Android Emulator (x86 64-bit and ARM v8-A); later the Lenovo Tab P12 Pro |
| Platform stability | No; provisional API level Sv2, and Google expected API changes before final |
The build already had what 12L is known for: the two-column notification shade and lock screen on screens above 600dp, the taskbar with drag-and-drop into split screen, and letterboxing that device makers can customise. Dave Burke’s post promised no breaking changes, so Google would not require apps to target 12L.
To use the new APIs, an app had to set compileSdkVersion,
targetSdkVersion and minSdkVersion to "Sv2". Google Play blocked
publishing apps that targeted Sv2. Google’s advice was to test the current
app in split screen with windows of several sizes and in the new
compatibility mode. Lenovo later offered the same Developer Preview 1 for its
Tab P12 Pro, the first real tablet that could run 12L.