Main announcements of KotlinConf 2025: new compiler and KMP

KotlinConf 2025 Conference: JetBrains Presented Revolutionary Updates

This year, the KotlinConf 2025 conference, organized by JetBrains, became a real event for the entire developer community. The event, held in a hybrid format, gathered thousands of participants worldwide. The main theme was the transformation of Kotlin from a "language for Android" into a full-fledged platform for cross-platform and server-side development. We have gathered for you the key announcements that are already changing the industry.

1. The Long-Awaited Stable Release of K2 Compiler

The main technical announcement of the conference is the promotion of the K2 compiler to stable status. The new version of the compiler, based on a redesigned architecture and using FIR (Frontend Intermediate Representation), promises:

• Build speedup of 2-3 times compared to the previous version.
• Reduced memory consumption in the IDE environment (IntelliJ IDEA, Android Studio).
• Full backward compatibility with code written in Kotlin 1.9 and above.
• Improved support for Multiplatform and Wasm.

Developers no longer need to enable experimental flags — K2 is enabled by default in Kotlin 2.1.

2. Kotlin Multiplatform (KMP) Goes into Production

JetBrains officially announced that Kotlin Multiplatform (KMP) is no longer an experimental technology. It is now a fully stable tool for creating shared business logic between iOS, Android, Web, and Desktop. Key improvements:

• Ready integration with Swift Package Manager for iOS.
• Native support for Compose Multiplatform for UI.
• Simplified Gradle module setup (a single configuration file is sufficient).

3. New AI Assistant: Kotlin Mentor

Artificial intelligence was also featured. JetBrains introduced Kotlin Mentor — a built-in AI assistant that works directly in the development environment. Unlike regular autocompletions, Mentor:

• Helps migrate code from Java and other languages to Kotlin.
• Suggests refactoring considering best practices (e.g., replacing callbacks with coroutines).
• Generates documentation and unit tests.

The feature is available in early access for IntelliJ IDEA Ultimate and Fleet subscribers.

4. Asynchrony: Structured Concurrency 2.0

The Kotlin Coroutines module received a major update. The main innovation is Structured Concurrency 2.0, which introduces a new model for managing the coroutine lifecycle. This simplifies error handling in complex asynchronous scenarios (e.g., in networking or when working with databases). Additionally, a new SharedFlow class with improved performance for processing data streams has been added.

5. Ecosystem and Community

The conference also announced partnerships with Google and Gradle to accelerate Android application builds. JetBrains promised to release a public b