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.



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