At KotlinConf 2025, JetBrains teased some of the new features that are coming to Kotlin in the next update to the language.

“From exciting language and ecosystem updates and robust AI tools that empower Kotlin development to major Kotlin Multiplatform milestones and a strategic partnership for the backend, KotlinConf 2025 brought a wave of news that set the tone for the year ahead,” JetBrains wrote in a blog post. 

In Kotlin 2.2, developers can look forward to guard conditions in when-with-subject, multi-dollar interpolation, non-local break and continue, and context parameters. 

JetBrains also revealed some language features that will be added to future releases after 2.2, including positional destructuring, name-based destructuring, enhanced nullability, rich errors, must-use return values, and ‘CheckReturnValue.’

The K2 compiler is now the default compiler in IntelliJ IDEA 2025.1, resulting in significant decreases in compilation time. According to JetBrains, using K2 for the IntelliJ monorepo that includes most JetBrains projects and contains over 12 million lines of Kotlin code decreased compilation time by over 40%. 

JetBrains explained that having the K2 compiler ready is enabling the Kotlin team to be more confident in the stability of compiler internals, allowing them to begin work on designing a new stable compiler plugin API for the frontend. This will extend the compiler with custom checks and code generation. 

The company is also continuing development of Amper, an experimental Kotlin and JVM build tool. It now has a clear configuration path, IDE support, and error reporting. 

Updates to Kotlin Multiplatform include a new plugin for IntelliJ IDEA and Android Studio, an experimental release of Swift Export that is coming to Kotlin 2.2.20, stable version of Compose Multiplatform for iOS, and Compose Hot Reload. 

Other updates from KotlinConf 2025 include:

  • Open-sourcing of Koog, a framework for developing AI agents in Kotlin
  • Updates to Kotlin/Wasm, such as faster incremental builds, smaller output binaries, and a better developer experience
  • Partnership with the Spring team to improve Kotlin for server-side work
  • Ktor 3 updates like enhanced configuration support, server-sent events, and WebAssembly support
  • Kotlin Language Server Protocol (LSP) and a new Kotlin extension for Visual Studio Code are in the early stages of development