Wednesday, 21 October 2026

Five things that changed in Android on 21 Oct.

2 min read

1. AppFunctions lets your app offer actions to on-device AI
This is how your app's features could become something an assistant can do for users without opening your app.
A new explainer walks through AppFunctions, an Android platform API with a Jetpack library. You mark suspend functions with an annotation, and agents such as Gemini can discover and call them on the device, much like tools on an MCP server. It needs Android 16, it is still an experimental preview, and Gemini access is limited to testers for now.
ProAndroidDev · CommunityRead the source
2. kotlinx.serialization 1.12.0 is stable
It is a low-risk update for any Kotlin app already on Kotlin 2.4.
alphabetarelease candidatestable1.12.0
The details
JetBrains released version 1.12.0 of kotlinx.serialization, the official Kotlin library for turning objects into JSON and other formats. It is built on Kotlin 2.4.10, includes everything from the release candidate, stabilises the serializer for Kotlin's Uuid type and removes stray whitespace from its Proguard rules.
kotlinx.serialization releases · LibraryRead the source
3. Media3 1.12 begins its alpha
Video apps can start trying frame-level metadata and wide-colour features before they reach stable.
alphabetarelease candidatestable1.12.0
The details
Media3, Android's Jetpack library for audio and video playback, released 1.12.0 alpha01. It adds a constant for the Display P3 colour space, a shared registry for feature flags, playlist and category fields in media metadata, and listeners that let ExoPlayer apps read metadata attached to each video frame.
AndroidX releases · OfficialRead the source
4. Android 17 QPR3 Beta 2 reaches Pixels with 21 fixes
If your app shows notification counts or targets Pixels, test it on the new beta.
The details
Google released the second beta of Android 17 QPR3, the quarterly platform update due in March 2027, for Pixel phones. According to 9to5Google it brings 21 fixes. Separate code findings suggest Pixel launcher will get numeric unread badges on app icons, a feature other Android skins have had for years.
9to5Google · Android · EcosystemRead the source
5. Not every coding-agent task needs a plan
It is practical advice on when planning saves time with agents and when it only slows you down.
The details
Chris Banes, maintainer of the Haze blur library for Compose, compares two real tasks done with a coding agent. One went fine with direct implementation, the other needed a written plan first. He explains how to tell the two apart and which checks matter either way, such as tests and reviewing the diff.
Chris Banes · ExpertRead the source