Your version of Kotlin runtime in 'Maven: org.jetbrains.kotlin:kotlin-stdlib:1.1.4' library is 1.1.4, while plugin version is 1.1.4-release-IJ2017.2-2.
This is with <kotlin.version>1.1.4-2</kotlin.version>.
Using 1.1.4 makes no difference.
There’s an answer in the stack overflow you linked to…You have to look at the error message and whatever is the -N at the end put that N in your kotlin.version
I use IntelliJ IDEA 2017.2.2, Build #IC-172.3757.52. Invalidating caches and restarting didn’t help. I also tried going to Maven Projects, cleaning and reimporting, to no avail.
EDIT: I should mention that everything builds and works perfectly, I just keep getting this warning.
That sounds like while you have 1.1.4-2 of the maven plug-in you have a kotlin-stdlib dependency that is still 1.1.4. Suggest searching for kotlin-stdlib in your project to check.