Kotlin 1.2.50 Early Access Preview


We’re happy to announce the Early Access Preview (EAP) build for Kotlin 1.2.50!

Getting the EAP build

For IntelliJ IDEA

You can configure Early Access Preview channel in ToolsKotlinConfigure Kotlin Plugin Updates. Change the update channel to ‘Early Access Preview 1.2.x’ and press Check for updates now.

For Maven or Gradle

Add the https://dl.bintray.com/kotlin/kotlin-eap repository URL to the list of project repositories. Here is how to do this in Gradle:

buildscript {
    ext.kotlin_version = '1.2.50-eap-17'

    repositories {
        maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }

    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

apply plugin: "kotlin"

repositories {
    maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }

dependencies {
    compile "org.jetbrains.kotlin:kotlin-stdlib"

Change the version of Kotlin dependencies (compiler and stdlib) to 1.2.50-eap-17.

The release notes could be viewed here.

Please provide feedback and report issues to our issue tracker. Please don’t forget to specify your IDE/build system Kotlin plugin versions.


A link to a change log would be nice, so that we know what to test.


Right, thanks. I added the link.


I get a problem with an abstractMethodError ( #KT-24462 ). Just a warning. As this happens already with gradle, try upgrading in gradle first (before updating the IDE plugin) as reverting in gradle is easier.


What versioning scheme is used for Kotlin? If I remember correctly the more recent versions were 1.2.30 -> 1.2.31 -> 1.2.40 -> 1.2.41. What happend to the numbers in between? It looks like there is a “.” missing or that the minor part (major.minor.patch) should be updated more frequently.

At least this scheme is a bit irritating. Is it explained somewhere?


This versioning scheme was announced in 1.1.50, there was some discussion about it.


Thanks! Answered in YouTrack.


I’ve had a quick look. Indeed it is likely to be the serialization plugin (for both gradle and idea). The github source has a revision that has a comment that claims compatibility with 1.2.50 but obviously that is not in the public released version of the plugin.


I can confirm that with a serialization idea plugin build from the kotlinx-serialization branch it works correctly.

pinned globally #10


Spring Framework and Spring Boot tests are green with 1.2.50-eap-17.


The second EAP/Release Candidate is available. The published version is 1.2.50-eap-62.
This is mainly bugfix release, but there are some interesting new things as well, including new experimental scripting API, improvements in the standard library, compiler and IDE. The detailed changes announcement will follow, while the current complete changelog could be viewed here.


I missed the scripting part in the release notes. Could you elaborate?


There are some discussions about it in the #scripting channel in kotlin slack. I’m now preparing an updated version of the scripting KEEP that will reflect the changes in this release. Hope that it will be ready next week. And then I’ll publish an additional announce here and in the kotlin slack.