JetBrains has released Kotlin 2.4.0. The update includes stable language features, standard library additions, Kotlin/Native changes for Swift interoperability, Kotlin/Wasm and Kotlin/JS improvements, and build tool updates for Gradle and Maven.
The release is included in the latest versions of IntelliJ IDEA and Android Studio. Projects can update by setting the Kotlin version to 2.4.0 in their build scripts.
Language and Standard Library
Several language features that were previously experimental are now stable, including context parameters, explicit backing fields, the @all meta-target for properties, and new defaulting rules for annotation use-site targets.
The common standard library now has a stable kotlin.uuid.Uuid API. Kotlin 2.4.0 also adds sorted-order checks such as .isSorted() and .isSortedBy(), plus JVM extensions for converting unsigned integers to BigInteger.
On Kotlin/JVM, the compiler can generate Java 26 bytecode, and annotations in Kotlin metadata are now enabled by default.
Kotlin/Native and KMP
For Kotlin Multiplatform projects, the main changes are in Kotlin/Native. Swift export is now Alpha and has improved concurrency support: Kotlin suspend functions are exported as Swift async counterparts, and kotlinx.coroutines flows can be exported to Swift as AsyncSequence.
KMP projects can also declare Swift packages as dependencies for iOS apps directly in Gradle configuration. JetBrains also provides migration support for projects that currently rely on CocoaPods dependencies.
Kotlin/Native now supports Xcode 26.4, updates LLVM to version 21, and enables the concurrent mark and sweep garbage collector by default. The default minimum supported Apple target versions have also been raised to iOS and tvOS 15.0, macOS 12.0, and watchOS 8.0.
Kotlin/Wasm incremental compilation is now stable and enabled by default. Kotlin 2.4.0 also introduces experimental support for the WebAssembly Component Model.
Kotlin/JS improves JavaScript and TypeScript export with support for value class export and ES2015 features when inlining JavaScript code.
On the build side, Kotlin 2.4.0 is compatible with Gradle 9.5.0. Maven builds now support automatic alignment between Java and JVM target versions.
Official announcement:
https://blog.jetbrains.com/kotlin/2026/06/kotlin-2-4-0-released/
Detailed release notes:
https://kotlinlang.org/docs/whatsnew24.html