Sorry missed your reply. That library seems like it is not maintained and jvm only. We built this initially for kotlin-js and then looked for the best jvm library to make it a proper multi platform library. We ended up using a java library that is a bit more mature than this one.
So, differences:
• mullti platform with js and jvm supported using two different libraries. Potentially extensible to other kotlin platforms (e.g. ios native)
• API is multi platform and works the same on all platforms. We use it in our spring boot server (notifications, email templates) and kotlin-js based web ui.
• Uses Kotlin language features to represent translation ids using enums that implement Translatable. This means you don't have a lot of hard coded strings all over your code base.