Kotlin Multiplatform v1.9.20-Beta2 Release Notes & Developer Guide

Kotlin 1.9.20-Beta2 focuses on stabilizing multiplatform and WebAssembly support with critical bug fixes. Key improvements include resolving kapt/ksp processing in commonMain, fixing configuration cache compatibility, and updating K/Wasm to final opcodes. This release addresses compiler crashes and dependency resolution issues that affected mobile and cross-platform developers.

Highlights

• WebAssembly backend updated to final opcodes for K/Wasm
• Fixed critical multiplatform bugs affecting kapt/ksp and configuration cache
• Improved expect/actual matching with better annotation handling in KMP
• Resolved concurrent modification and dependency ordering issues in MPP builds
• Enhanced K2 compiler plugin API for metadata annotation handling