Google released the first developer preview of Android 12 on 18 February 2021, eight months before the Pixel rollout. Dave Burke’s post called it “just the start”, and Android Beta was not open for it.
| Release date | 18 February 2021; Developer Preview 1.1 on 3 March 2021 |
| Build | SPP1.210122.020.A3; 1.1 SPP1.210122.022 |
| Security patch | February 2021; 1.1 March 2021 |
| Devices | Pixel 3, 3a, 4, 4a, 4a 5G and 5; 64-bit Android Emulator images; a separate Android TV build |
| How to get it | Flash a factory image, or sideload an OTA image on a Pixel running Android 11, without a wipe |
| Platform stability | No; Google expected it by August 2021 |
The rules that later defined targeting API 31 were already here:
components with an intent filter had to declare android:exported, every
PendingIntent needed FLAG_MUTABLE or the new FLAG_IMMUTABLE, and
foreground services could no longer start from the background. To replace
them Google added expedited jobs to JobScheduler and WorkManager.
Notification trampolines were blocked for apps targeting the new platform,
and every app got a toast when it used one.
The build also brought compatible media transcoding from HEVC to AVC, AVIF
images, OnReceiveContentListener for rich content, haptics coupled to an
audio session, and WebView’s SameSite cookie behaviour. The Netlink MAC
restriction from Android 11 now applied to every app, whatever its target.
ART became a Mainline module. Most behaviour changes could be toggled one by
one from Developer options or adb.
Developer Preview 1.1 fixed Wi-Fi drops, a System UI crash on screenshots from the lock screen, battery drain from partial wake locks, and an unresponsive fingerprint reader.