# Kotlin v2.4.20-RC released!

**URL:** <https://forum.devtalk.com/t/kotlin-v2-4-20-rc-released/248769>\
**Category:** Backend Official News\
**Tags:** newsbot, official-news, kotlin\
**Created:** [12 August 2026 12:24 UTC](https://forum.devtalk.com/t/kotlin-v2-4-20-rc-released/248769 "2026-08-12T12:24:24Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![NewsBot](https://forum.devtalk.com/user_avatar/forum.devtalk.com/newsbot/32/1114_2.png) [@NewsBot](https://forum.devtalk.com/u/NewsBot)\
**Post date:** [12 August 2026 12:24 UTC](https://forum.devtalk.com/t/kotlin-v2-4-20-rc-released/248769/1 "2026-08-12T12:24:24Z")

</div>

[Kotlin](https://devtalk.com/kotlin) v2.4.20-RC has been released.

> [@](#):
>
> ## Changelog
> 
> ### Backend. J2KLIB
> 
> - [`KT-88165`](https://youtrack.jetbrains.com/issue/KT-88165) Add Support for -XheaderModeType=compilation to improve header compilation performance
> - [`KT-86239`](https://youtrack.jetbrains.com/issue/KT-86239) [JKLIB] Investigate which type system context is needed in JklibIrLinker
> - [`KT-88306`](https://youtrack.jetbrains.com/issue/KT-88306) [JKLIB] Unbound symbols for kotlin.coroutines.SuspendFunctionN
> - [`KT-88120`](https://youtrack.jetbrains.com/issue/KT-88120) [JKLIB] Add -jvm-target to K2JKlibCompilerArguments
> - [`KT-88176`](https://youtrack.jetbrains.com/issue/KT-88176) [JKLIB] DeserializationStrategy.WITH\_INLINE\_BODIES when deserializaing dependencies
> - [`KT-88163`](https://youtrack.jetbrains.com/issue/KT-88163) Allow to disable firAggressivePrunner for Jklib
> 
> ### Compiler
> 
> - [`KT-87499`](https://youtrack.jetbrains.com/issue/KT-87499) ClassCastException “Float cannot be cast to Unit” when a suspend function’s result is discarded in a when-branch
> - [`KT-87983`](https://youtrack.jetbrains.com/issue/KT-87983) CCE on member extension property delegated to bound property reference
> - [`KT-85403`](https://youtrack.jetbrains.com/issue/KT-85403) kotlin.NoWhenBranchMatchedException on Kotlin Native with sealed interface
> - [`KT-87922`](https://youtrack.jetbrains.com/issue/KT-87922) K1FakeDescriptorsForReferencesKt classes duplicated between kotlin-scripting-compiler-embeddable and kotlin-build-tools-impl
> - [`KT-86657`](https://youtrack.jetbrains.com/issue/KT-86657) Native: turn on incremental compilation by default
> 
> ### Compose compiler
> 
> - [`b/543684938`](https://issuetracker.google.com/issues/543684938) Fix composable singleton in function with type parameters
> - [`b/537617330`](https://issuetracker.google.com/issues/537617330) Fixed a bug that caused miscompilation of cross-module calls  
> to getters and setters, causing spurious runtime errors.
> 
> ### JVM. Reflection
> 
> - [`KT-87369`]([https://youtrack](https://youtrack)…

Link: [Release Kotlin 2.4.20-RC · JetBrains/kotlin · GitHub](https://github.com/JetBrains/kotlin/releases/tag/v2.4.20-RC)