Good morning! I wanted to try out K2, but I cannot activate it in my project. When I add the code snippet from the instructions to the build.gradle.kts, I get

Incorrect language version. Expected one of: '1.0', '1.1', '1.2', '1.3', '1.4', '1.5', '1.6', '1.7', '1.8', '1.9'

(with plugin 1.8.20). Any ideas?

kotlin {
    sourceSets.all {
        languageSettings {
            languageVersion = "2.0"
        }
    }
}

Please make sure you're using Kotlin 1.8.20 Gradle plugin

image.png

Highly likely you have some other kotlin plugin block somewhere in your gradle configuration Search for "org.jetbrains.kotlin.jvm" across the sources of your gradle files

You are correct. I started this project through an nx template, and it had a variable

kotlinJvmVersion

defined as

1.8.0

. That tricked me into thinking it was a JVM language version, which of course would also not be exactly right. Maybe it’s because I have to work with Java 1.8 in client projects a lot …

Ah! It happens sometimes, especially when working with templates Great to know that you found it 🙂