## Version 4.0.0

_2019-06-26_

**This release upgrades OkHttp to Kotlin.** We tried our best to make fast and safe to upgrade
from OkHttp 3.x. We wrote an [upgrade guide][upgrading_to_okhttp_4] to help with the migration and a
[blog post][okhttp4_blog_post] to explain it.

 *  Fix: Target Java 8 bytecode for Java and Kotlin.


## Version 4.0.0-RC3

    val response = get(server.url("/"))
    assertThat(response.header("")).isEqualTo("A")
    assertThat(response.body.string()).isEqualTo("body")
  }

  /**
   * Old implementations of OkHttp's response cache wrote header fields like ":status: 200 OK". This
   * broke our cached response parser because it split on the first colon. This regression test
   * exists to help us read these old bad cache entries.
   *