Kotlin older versions support

[LikeTheSalad]

Hi!

Some people seem to struggle with upgrading Kotlin in their projects, as shown in this issue, and, because of compatibility issues, if a dependency uses a higher version of Kotlin than the one set in the host project, the Kotlin plugin will complain and refuse to compile :/ which is why we recently decided to provide older language version compatibility support here.

So I was wondering if using the languageVersion/apiVersion config options to provide support for older versions of Kotlin has or could be considered for this project?

[yschimke]

@swankjesse I've been following okio versions mainly, do we have a clear strategy for this?

[swankjesse]

In general, the latest OkHttp will use the latest Okio and the latest Kotlin dependencies. All three libraries follow very strict compatibility rules.

It is safe to compile against OkHttp version X and run against version Y as long as Y >= X, even across major version changes.

If for whatever reason you must run with on an old version of Kotlin, find an old version of OkHttp that uses that old version of Kotlin. Typically this is necessary for Gradle plugins that run in old versions of Gradle.

[LikeTheSalad]

I see, thank you. One important, recurring concern about using older versions is security. Since you're suggesting using older versions of OkHttp, is it safe to say that those older versions get security updates too? @swankjesse

[yschimke]

No. Only 4.x and 5 alpha get security fixes

If you are concerned about security fixes you'll likely be on the latest kotlin also.