It's still very early and very alpha - enough that it'll probably massively block at least one of your important production releases.

It's promising though, although it doesn't really solve the same kind of issues as Flutter - Flutter is a UI library first and formost. While Kotlin Multiplatform will most likely replace cases where we use C++ for porability now - internal, shared libraries.

I've used Kotlin Native around 6 months ago, which seems to be the iOS target for Kotlin Multiplatform. I ended up switching to Go, as much as I didn't want to, because of memory leaks when interacting with the official HTTP client (Ktor). The multithreading through coroutines is pretty experimental and unstable.

The community is small, and there is not a lot of actually multiplatform Kotlin libraries, although I saw some libraries making progress towards it. I found myself having to write bindings to C libraries a lot.

The language is very promising though, it's great with the JVM or JS as target.