What's new in Kotlin for KMM

Kotlin 1.5.30 for KMM

Kotlin 1.5.30 introduces a number of improvements and features that are helpful for KMM:

• Apple silicon support. Kotlin 1.5.30 introduces native support for Apple silicon. Now the Kotlin/Native compiler and tooling can run on Apple silicon hardware without Rosetta translation environment

  Learn more about Apple silicon support.

• Improved Kotlin DSL for CocoaPods Gradle plugin. Kotlin 1.5.30 introduces the improved CocoaPods Gradle plugin DSL. In addition to the name of the framework, you can now specify other parameters in the pod configuration:

  • Dynamic or static version of the framework

  • Dependencies explicit export

  • Bitcode embedding

  • Custom names for Xcode configuration

  Learn more about CocoaPods Gradle plugin improvements.

• Experimental interoperability with Swift 5.5 async/await. The Kotlin/Native compiler now emits the _Nullable_result attribute in the generated Objective-C headers for suspending functions with nullable return types. This makes it possible to call them from Swift as async functions with the proper nullability.

  Learn more about experimental interoperability with Swift 5.5 async/await.

• Improved Swift/Objective-C mapping for objects and companion objects. Getting objects and companion objects can now be done in a way that is more intuitive for native iOS developers.

  Learn more about mapping for objects and companion objects.

• Sharing custom cinterop libraries between platforms. Starting from Kotlin 1.5.30, you can use custom cinterop libraries in shared native code.

  Learn more about sharing custom cinterop libraries between platforms.

• Support for XCFrameworks. Now all Kotlin Multiplatform projects can use XCFrameworks.

  Learn more about support for XCFrameworks.

• New default publishing setup for Android artifacts. Kotlin 1.5.30 brings new default publishing setup for Android artefacts. You can publish your multiplatform library for the Android target by specifying Android variant names in the build script. The Kotlin Gradle plugin will generate publications automatically.

  Learn more about new default publishing setup for Android artifacts.

Kotlin 1.5.20 for KMM

Kotlin 1.5.20 introduces a number of improvements and features that are helpful for KMM:

• Export of KDoc comments to generated Objective-C headers. You can now set the Kotlin/Native compiler to export the documentation comments (KDoc) from Kotlin code to the Objective-C frameworks generated from it, making them visible to the frameworks’ consumers.

  This feature is experimental. We would appreciate your feedback on it in YouTrack.

  Learn more about exporting KDoc comments to generated Objective-C headers and how to opt in to this feature.

• New framework-packing task for Kotlin/Native. The Kotlin Multiplatform Gradle plugin now includes the embedAndSignAppleFrameworkForXcode task, which can be used from Xcode to connect KMM modules to the iOS part of your project.

  Check out this blog post to learn about the new framework-packing task and how to remove from the packForXcode task from your build script.

Learn more about what's new in Kotlin 1.5.20.

Kotlin 1.5.0 for KMM

Kotlin 1.5.0 introduces a number of improvements and features that are helpful for KMM:

• Simplified test dependency selection for each platform. Now you can use the kotlin-test dependency to add dependencies for testing in the commonTest source set. The Gradle plugin will infer the corresponding platform dependencies for each test source set:

  • kotlin-test-junit for JVM source sets.

  • kotlin-test-common and kotlin-test-annotations-common for common source sets.

  iOS source sets use Kotlin/Native, which has everything built in, so they do not require any additional artifacts.

  You can also use the kotlin-test dependency in any shared or platform-specific source set. Learn more about setting dependencies on test libraries.

• New API for getting a char’s Unicode category. A variety of new character-related functions are available on all platforms and in the common code. They include several functions for checking whether a char is a letter or a digit, like Char.isLetterOrDigit(), as well as functions for checking the case of a char, like Char.isUpperCase(). The property Char.category and the enum class CharCategory are available, as well.
  Learn more about this new API.

• Improved Kotlin/Native performance and stability. Kotlin/Native is receiving a set of performance improvements that speed up both compilation and execution.
  Learn more about the Kotlin/Native improvements.

Learn more about what's new in Kotlin 1.5.0.

Kotlin 1.4.30 for KMM

Kotlin 1.4.30 introduces a number of improvements that are helpful for KMM:

• Improved compilation time for an iOS simulator. Recompiling binaries for the iOS simulator after making changes in the code now requires much less time. You can see the most significant improvements when re-running unit tests or applications on the iOS simulator. For example, the time required to rebuild the framework in the KMM Networking and data storage sample has decreased from 9.5 seconds (in 1.4.10) to 4.5 seconds (in 1.4.30).
  These optimizations affect other scenarios as well.

• Support for libraries delivered in Xcode 12.2.

• Support for the new watchosX64 target in Kotlin/Native. This target makes it possible to run the simulator on 64-bit architecture.

Learn more about what's new in Kotlin 1.4.30.

Kotlin 1.4.20 for KMM

Kotlin 1.4.20 introduces a number of features, improvements, and bug fixes that are helpful for KMM:

• CocoaPods plugin improvements:

  • Rebuilding dependencies only when necessary.

  • Ability to add dependencies on libraries from a custom spec repository, Git repository, or archive, as well as on libraries with custom cinterop options.

    
    

    Learn more about adding CocoaPods dependencies and these improvements.

• Support for libraries delivered in Xcode 12.

• Escape analysis for Kotlin/Native. A prototype of a new mechanism that gives a 10% iOS runtime performance improvement by allocating certain objects on the stack instead of the heap.

• Opt-in wrapping of Objective-C exceptions in runtime to avoid crashes. Learn how to opt in.

• Updated structure of multiplatform library publications. The library root publication, which stands for the whole library, now includes metadata artifacts. These were published separately in earlier Kotlin versions.
  For compatibility, both multiplatform library authors and users must update to Kotlin 1.4.20. Learn more about publishing a multiplatform library.

• Deprecation of the Kotlin Android Extensions plugin. The Parcelable implementation generator has been moved to a separate kotlin-parcelize plugin.

Learn more about what's new in Kotlin 1.4.20.