ktor

1. Keep the Kotlin Gradle plugin new enough to support the configured JVM toolchain

compileKotlin and compileJava must target the same JVM bytecode version. When a module sets:

kotlin {
    jvmToolchain(25)
}

Gradle applies toolchain 25 to both tasks, but the Kotlin compiler silently caps compileKotlin to the highest JVM target it supports, which lags behind the JDK's own release cadence. An old kotlin("jvm") plugin version (e.g. 2.1.21) paired with a new toolchain (e.g. 25) produces:

❌ Inconsistent JVM Target Compatibility Between Java and Kotlin Tasks
Inconsistent JVM-target compatibility detected for tasks 'compileJava' (25) and 'compileKotlin' (23).

Fix by bumping the Kotlin Gradle plugin version in plugins { kotlin("jvm") version "..." } to a release that supports the toolchain's JVM target, rather than lowering the toolchain. Match the Kotlin version already used by other modules in the repo that target the same JVM (e.g. online-product-shop uses 2.3.0 with JavaLanguageVersion.of(25)).

Checklist

[] kotlin("jvm") plugin version supports the JVM version set by jvmToolchain(...) / JavaLanguageVersion.of(...) [] ./gradlew compileKotlin compileJava succeeds with no "Inconsistent JVM Target Compatibility" error