Kotlin 2.4, 2.4.20 and the road to 2.5

In the language: context parameters, except context arguments and callable references, the @all meta-target for properties, new defaulting rules for annotation use-site targets, and explicit backing fields. In the standard library, the common UUID API and sorted-order checks are stable. Kotlin/JVM supports Java 26, and Gradle compatibility reaches 9.5.0. New experimental pieces include collection literals with [] brackets, explicit context arguments, and an @IntroducedAt annotation for version-based overloads. On the Apple side, Kotlin Multiplatform projects can declare Swift packages as dependencies, and Swift export moved to Alpha.

On the JVM, compiling when expressions with invokedynamic on JVM 21 and later is now stable and on by default. The standard library adds a StackTraceRecoverable interface so exceptions with extra constructor arguments keep useful coroutine stack traces, plus experimental allDistinct() and allDistinctBy() checks and new kotlin.test overloads. Swift export now maps sealed classes and interfaces to Swift enums, so switches in Xcode can be exhaustive, and supports cross-language inheritance; assembleSharedXCFramework generates a Package.swift for SwiftPM dependencies. Incremental compilation of klibs is in Beta behind kotlin.incremental.native=true. Kotlin/Wasm can run wasmWasi on Wasmtime, and Gradle support reaches 9.7.0. The compiler gains a kotlinr runner command.

Set the plugin version to 2.4.20, for example kotlin("jvm") version "2.4.20" or the matching entry in your version catalog, and update your IDE. On Android, AGP 9’s built-in Kotlin already depends on the Kotlin Gradle plugin 2.2.10; to use 2.4.20, declare the newer plugin in your top-level buildscript classpath as Google describes. Check the Wasm notes before updating if you use require() inside @JsFun: it now reports an error, and JetBrains points to @JsModule instead.

Kotlin ships a language release every six months and a tooling release three months after each. From 2.4.0, each release line of the JVM standard library has an 18-month support window: the 2.4 line is supported until December 3, 2027. Security fixes are built on the latest release of a line, so on the 2.4 line they would come as an update to 2.4.20, not to 2.4.0.

New language features help you ship; being found brings people to what you ship. Censuus ranks apps by the visits they draw, and adding your app is free through the List my app form. Placement comes from traffic and sponsorship: apps climb on the visits they draw, and a sponsor can pay to rise higher. For shared UI on iOS, see Compose Multiplatform and Liquid Glass, and for navigation, Navigation 3.