I have a library that is still targeting language ...

# library-development

[Matthew Pope]

I have a library that is still targeting language level 1.4 and API level 1.3. In some language ecosystems, it's considered okay to upgrade your compiler version/build toolchain as a minor version. What's the consensus for Kotlin in this case? Should I release a new major version if I update to language level 1.6 and API level 1.5?

[mbonnin]

I'd say as long as you do not use newer language features in your public API, it should be fine to update in a minor version. Everything is backward compatible so you can even use new stdlib APIs (like lowercase for an example) and dependency resolution should pickup the latest version of stdlib

[mbonnin]

Your consumers will need to update their own version of the Kotlin compiler though so that could be technically considered a (source?) breaking change I believe

[mbonnin]

If you're that much concerned, you could keep language level to 1.4 I guess. What do you need in 1.6 specifically?

[Matthew Pope]

I want to start using sealed interfaces. It's not strictly a need for my use case, but it would be awfully useful.

[mbonnin]

Makes sense 👍 . I think I'd upgrade in a minor version and put a note in the release notes. With language level 1.6, your consumers will need Kotlin 1.5 to compile which is now 2 years old. I think it's very reasonnable at this stage. A lot of libs are updating at a faster pace