Kotlin Multiplatform v2.5.0-Beta1 Release Notes & Developer Guide

Kotlin 2.5.0-Beta1 introduces strict equals checks with improved smart casting, JVM bytecode version 27 support, and a reworked class initialization scheme for Kotlin/Native and JVM companion blocks. The release brings significant performance and infrastructure improvements to the Analysis API, including Standalone mode optimizations and stub-based decompiler enhancements. K/Wasm continues to mature with coroutine handling fixes, companion block support, and new stdlib exports for WASM components.

Highlights

• Added JVM target bytecode version 27 support for newer Java runtimes
• Introduced Strict equals checks with smart casts based on equality bound types
• Kotlin/Native now uses JVM-like class initialization scheme with companion blocks and extensions
• K/Wasm exports cabi_realloc function from stdlib to support WASM components
• Added initial support for release compiler caches to speed up Kotlin/Native builds
• Analysis API Standalone gains proper library publishing structure and performance optimizations
• Improved decompiled text and stub support for annotations and multi-field value classes