IntelliJ Idea 2017.3 unable to start Kotlin Spring Boot App - @Configuration class may not be final

Question

I was able to launch a Spring Boot Kotlin App from IntelliJ 2017.3. After the last IntelliJ fix update I cannot start that application from the IDE, getting this exception:<

Answer 1

Fixed upgrading IntelliJ's Kotlin pluging to 1.2.21: https://plugins.jetbrains.com/plugin/6954-kotlin/update/42501