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Kotlin Tutorial · Kotlin Basics · Lesson 11 of 31

Kotlin History & Versions

How Kotlin grew from a JetBrains project into Google's preferred language for Android, the K2 compiler, Kotlin Multiplatform, the release cadence, and which version to use today.

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How Kotlin started

JetBrains, the company behind IntelliJ IDEA, started Kotlin in 2010 because it wanted a more productive language than Java for its own products that still worked with every Java library. It was announced in July 2011 and named after Kotlin Island near St Petersburg, where much of the team worked. Kotlin 1.0 was released on 15 February 2016 with a promise of backward compatibility.

Timeline of major releases

  1. Kotlin 2.4Current
    • Context parameters and explicit backing fields become stable (2.4.20 followed on 2026-09-07)
  2. Kotlin 2.3Historic
    • Nested type aliases and data-flow-based exhaustiveness checks for when; unused return value checker (preview)
  3. Kotlin 2.2Historic
    • Guard conditions in when, non-local break/continue and multi-dollar interpolation become stable; context parameters (preview)
  4. Kotlin 2.1Historic
    • Previews of guard conditions, non-local break and continue, and multi-dollar string interpolation
  5. Kotlin 2.0Historic
    • The new K2 compiler becomes stable: faster compilation and one front end for every platform
  6. Kotlin 1.9.20Historic
    • Kotlin Multiplatform becomes stable
  7. Kotlin 1.9Historic
    • The ..< operator, data object and enum.entries become stable
  8. Kotlin 1.5Historic
    • Sealed interfaces, value classes and JVM records
  9. Kotlin 1.4Historic
    • SAM conversions for Kotlin interfaces, trailing commas and explicit API mode
  10. Kotlin 1.3Historic
    • Coroutines become stable
  11. Kotlin 1.1Historic
    • Experimental coroutines and the JavaScript target
  12. Kotlin 1.0Historic
    • The first stable release

Turning points

  • Android (2017 and 2019): at Google I/O in May 2017 Google announced official Kotlin support on Android, and in May 2019 it declared Android development Kotlin-first. Most new Android code is now Kotlin, and Jetpack Compose (stable in 2021) is a Kotlin-only UI toolkit.
  • The Kotlin Foundation (2017): created by JetBrains and Google to protect and advance the language.
  • Coroutines (2018): stable coroutines made asynchronous code look sequential and shaped Android and server frameworks such as Ktor.
  • Kotlin Multiplatform (2023): sharing code between Android, iOS, desktop and web became stable; Compose Multiplatform later brought shared UI to iOS.
  • K2 (2024): a rewritten compiler that made Kotlin 2.0 faster and the base for new language features.

Release cadence

Kotlin ships a language release (2.x.0) about every six months and tooling releases (2.x.20) in between, plus bug-fix updates. New features usually go through Experimental, Alpha and Beta stages before they become stable.

Which version should I use?

Use the latest 2.x release for new projects. Android projects follow the Kotlin version supported by the current Android Gradle Plugin and Compose compiler, which is usually the latest one.

Further reading: What's new in Kotlin · Kotlin releases · Kotlin Foundation

Last reviewed 21 October 2026. Release and support dates come from the official release pages linked above.

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