Incompatible Gradle and Kotlin comes with IntelliJ IDEA 2025.3.1

IntelliJ Platform
2

Hi, JetBrains IDEs 2025.3 still use JBR 21 runtime and you will not be able to use JDK 25 classes and bytecode target for plugins until we switch to 25.

The plan is to update runtime to 25 in 2026.1 versions starting with EAP

Kotlin: Unknown JVM target version: 25