Please welcome the latest Kotlin M4 release that includes 128 closed issues since M3.1. Full details on the M4 release can be found on the Kotlin Blog. While there are many highlights such as being faster, JDK7-friendly and code completion improvements; there are also noteworthy IDE improvements for IntelliJ IDEA 12. IDE Improvements: Run All Tests in a Directory. Now IntelliJ IDEA can discover tests written in Kotlin, so that you can run all tests in directory/package: Java ones as well as Kotlin ones. Debugger. Many fixes including receivers of extension functions/properties are now