| com.squareup.okhttp3:mockwebserver:5.0.0         | okhttp3.mockwebserver | Obsolete. Depends on JUnit 4.     |

**OkHttp now supports Happy Eyeballs ([RFC 8305][rfc_8305]) for IPv4+IPv6 networks.** It attempts
both IPv6 and IPv4 connections concurrently, keeping whichever connects first.

**We’ve improved our Kotlin APIs.** You can skip the builder:

```kotlin

    /**
     * Configure this client to perform fast fallbacks by attempting multiple connections
     * concurrently, returning once any connection connects successfully.
     *
     * This implements Happy Eyeballs ([RFC 6555][rfc_6555]), balancing connect latency vs.
     * wasted resources.
     *
     * Defaults to enabled, call with [fastFallback] = false to revert to 4.x behaviour.
     *