Upgrading to OkHttp 4
=====================

OkHttp 4.x upgrades our implementation language from Java to Kotlin and keeps everything else the
same. We’ve chosen Kotlin because it gives us powerful new capabilities while integrating closely
with Java.

We spent a lot of time and energy on retaining strict compatibility with OkHttp 3.x. We’re even
keeping the package name the same: `okhttp3`!

There are three kinds of compatibility we’re tracking:

  - 'Works with OkHttp': works_with_okhttp.md
  - 'API': 5.x/okhttp/okhttp3/
  - 'Change Logs':
    - 'Change Log': changelogs/changelog.md
    - '4.x Change Log': changelogs/changelog_4x.md
    - 'Upgrading to OkHttp 4': changelogs/upgrading_to_okhttp_4.md
    - '3.x Change Log': changelogs/changelog_3x.md
    - '2.x Change Log': changelogs/changelog_2x.md
    - '1.x Change Log': changelogs/changelog_1x.md
  - 'Contributing':

Deployment objects you created in 1.1 won’t work with in the 1.2 release.
     * Before upgrading to 1.2, <strong>delete all Deployment alpha-version resources</strong>, including the Replication Controllers and Pods the Deployment manages. Then
create Deployment Beta resources after upgrading to 1.2. Not deleting the
Deployment objects may cause the deployment controller to mistakenly match

 *  Fix: Don't crash on concurrent modification of `SPDY` SPDY settings.

## Version 2.0.0

This release commits to a stable 2.0 API. Read the 2.0.0-RC1 changes for advice
on upgrading from 1.x to 2.x.

_2014-06-21_

 *  **API Change**: Use `IOException` in `Callback.onFailure()`. This is
    a source-incompatible change, and is different from OkHttp 2.0.0-RC2 which
    used `Throwable`.

    - [kubectl delete: < v1.4.0 client vs >=v1.4.0 cluster](#kubectl-delete--v140-client-vs-v140-cluster)
    - [DELETE operation in REST API](#delete-operation-in-rest-api)
  - [Action Required Before Upgrading](#action-required-before-upgrading)
- [optionally, remove the old secret](#optionally-remove-the-old-secret)
  - [Previous Releases Included in v1.4.0](#previous-releases-included-in-v140)
- [v1.4.0-beta.11](#v140-beta11)

### Internal Storage Layer

 * Use [Builder.allEnabledTlsVersions] and [Builder.allEnabledCipherSuites] to defer all feature
 * selection to the underlying SSL socket.
 *
 * The configuration of each spec changes with each OkHttp release. This is annoying: upgrading
 * your OkHttp library can break connectivity to certain web servers! But it’s a necessary annoyance
 * because the TLS ecosystem is dynamic and staying up to date is necessary to stay secure. See

  - [Features](#features)
  - [Known Issues](#known-issues)
  - [Notable Changes to Existing Behavior](#notable-changes-to-existing-behavior)
  - [Deprecations](#deprecations)
  - [Action Required Before Upgrading](#action-required-before-upgrading)
  - [External Dependency Version Information](#external-dependency-version-information)
  - [Changelog since v1.5.0-beta.3](#changelog-since-v150-beta3)
    - [Other notable changes](#other-notable-changes-7)

    - [Other notable changes](#other-notable-changes-9)
- [v1.3.0](#v130)
  - [Downloads](#downloads-9)
  - [Highlights](#highlights)
  - [Known Issues and Important Steps before Upgrading](#known-issues-and-important-steps-before-upgrading)
      - [ThirdPartyResource](#thirdpartyresource)
      - [kubectl](#kubectl)
      - [kubernetes Core Known Issues](#kubernetes-core-known-issues)

    why we're doing this and how to upgrade.

    The OkHttp 3.12.x branch will be our long-term branch for Android 2.3+ (API level 9+) and Java
    7+. These platforms lack support for TLS 1.2 and should not be used. But because upgrading is
    difficult we will backport critical fixes to the 3.12.x branch through December 31, 2021. (This
    commitment was originally through December 31, 2020; we have since extended it.)