2026 is a big year for the Android build ecosystem. We've all been frustrated by how the Android build system has worked — bugs, memory leaks, DSL magic, and various workarounds that both official and OSS tools end up doing just to make the system compile. It all works on the surface, but small changes to these systems become a big problem, which leads us to the "don't touch it if it works" model. That doesn't work anymore. This talk goes through legacy AGP/KGP features that are still enabled by default, why that's the case, and how we should be changing things here — plus how to stay forward compatible without turning features on before they're ready for us. From there we get into the new Gradle features and how they fix some of the old painful sins: Configuration Cache and why it's taken two years to get close to becoming default, Project Isolation and whether it actually works better than Configuration Cache, the Foojay toolchain resolver and why we should always be updating the JVM we build with, and the Gradle Errors API. On the Android side: the changes in the DSL, KMP getting integrated directly into the AGP plugin, build types being removed from KMP, and what gets removed in AGP 10 versus just deprecated in AGP 9. On the Kotlin side: the Build Tools API, backward/forward compatibility layers, annotations support in Kotlin metadata, and K2 kapt. I will also cover other new exciting things to look forward to in Kotlin. Lastly, long standing open issues on Gradle, Kotlin and AGP — which ones eventually get fixed, how to work around the ones that don't, and why "wontfix" is really an anti-pattern we should be pushing back on.