Uh Oh!

Something went wrong.
Don’t worry, it’s not you — it’s us.
Sorry about that!

K2 compiler migration guide
Performance improvements
Language feature improvements
Smart casts
Kotlin Multiplatform
How to enable the Kotlin K2 compiler
Use Kotlin build reports with Gradle
Support in IDEs
Try the Kotlin K2 compiler in the Kotlin Playground
How to roll back to the previous compiler
Changes
Immediate initialization of open properties with backing fields
Deprecated synthetics setter on a projected receiver
Forbidden use of inaccessible generic types
Consistent resolution order of Kotlin properties and Java fields with the same name
Improved null safety for Java primitive arrays
Stricter rules for abstract members in expected classes
Per subject area
Compatibility with Kotlin releases
Compatibility with Kotlin libraries
Compiler plugins support
Upgrade your custom compiler plugins
Share your feedback on the new K2 compiler

Kotlin™ is protected under the Kotlin Foundation and licensed under the Apache 2 license.

Supported and developed by JetBrains