Kotlin Compiler Now Requires JDK 17 Starting With Version 2.5.0
The Kotlin compiler has officially transitioned to requiring JDK 17 or newer for all environments, starting with version 2.5.0 and becoming mandatory in version 2.5.20-Beta1.
The Kotlin compiler requires JDK 17 as its minimum required runtime, starting its transition with version 2.5.0-Beta1.
If you run the compiler on an older version of the Java Development Kit, version 2.5.0-Beta1 issues a warning. Releases 2.5.0-Beta2 and stable 2.5.0 escalate this warning to an error. A flag permits temporary use of older environments during this window.
Starting with 2.5.20-Beta1 and all subsequent versions, JDK 17 or newer becomes mandatory without exception for all environments, including local development machines and continuous integration pipelines.
If this requirement creates blockers for your use cases, leave feedback on the project issue tracker under reference KT-88173.