Kotlin Multiplatform Jul 10, 2025 Pre-release

v2.2.20-Beta1

What's New

Kotlin 2.2.20-Beta1 delivers significant Analysis API stability improvements addressing red code issues in K2 IDE, enhanced contract support for operators and extension properties, and substantial Wasm backend optimizations. The release introduces KMP parser components and data-flow based exhaustiveness analysis while removing legacy internal APIs from Native and Wasm standard libraries.

Highlights

Breaking Changes

  • Removed multi-field value class representation from metadata
  • Removed kotlin.native.internal.Ref class from standard library
  • Removed kotlin.wasm.internal.ClosureBox classes from standard library

Deprecations

  • Deprecated Analysis API methods marked for removal
  • ForbidInferOfInvisibleTypeAsReifiedOrVararg changed from error to warning
  • PARAMETER_NAME_CHANGED_ON_OVERRIDE suppression removed in KMP lexers

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