Kotlin Multiplatform v2.1.0-Beta1 Release Notes & Developer Guide
What's New for Developers
Kotlin v2.1.0-Beta1 strengthens the K2 compiler with 100+ fixes addressing type system edge cases, exhaustiveness checking, and diagnostics accuracy. The Analysis API gains property and operator resolution support while light classes now handle value classes properly. Performance improvements in IDE operations and new debugging capabilities for Kotlin/Wasm enhance the overall developer experience across mobile and multiplatform development.
Highlights
- Analysis API enhancements: property and operator support in resolveToCallCandidates
- Light classes now support value classes and companion objects within value classes
- Swift export auto-linkage of binary dependencies for Apple ecosystem
- Kotlin/Wasm debugging improvements for variable inspection in Chrome/Firefox
- Extensive K2 compiler fixes addressing type inference, exhaustiveness checking, and diagnostics
- Performance improvements in visibility checking and symbol caching for faster IDE operations
Breaking Changes
- Using -Xuse-k2 compiler flag is now an error; use -language-version 2.1 instead
- Bitcode embedding support deprecated and removed from Kotlin Gradle plugin for Apple targets
Deprecations
- Various Analysis API declarations marked for stabilization and cleanup
- Reified modifier on type alias parameters deprecated
- Synchronized, Throws, JvmField annotations on annotation parameters deprecated
Recent Releases
All releases →
v2.5.0-Beta2
Oct 21, 2026
Release Notes →
v2.4.21
Oct 8, 2026
Release Notes →
v2.4.21-RC
Sep 30, 2026
Release Notes →
v2.5.0-Beta1
Sep 23, 2026
Release Notes →
v2.4.20
Sep 7, 2026
Release Notes →
v2.4.20-RC3
Sep 2, 2026
Release Notes →
v2.4.20-RC2
Aug 26, 2026
Release Notes →
v2.4.20-RC
Aug 12, 2026
Release Notes →
v2.4.20-Beta2
Jul 22, 2026
Release Notes →
v2.4.10
Jul 14, 2026
Release Notes →
v2.4.10-RC2
Jul 7, 2026
Release Notes →