anchor.diff:  [id="understanding-upgrade-channels_{context}"]
   = {product-title} upgrade channels and releases
   
  -In {product-title} 4.1, Red Hat introduced the concept of channels for
  -recommending the appropriate release versions for cluster upgrade. By controlling
  -the pace of upgrades, these upgrade channels allow you to choose an upgrade
  -strategy. Upgrade channels are tied to a minor version of
  -{product-title}. For instance, {product-title} 4.7
  -upgrade channels will never include an upgrade to a 4.8 release. This strategy ensures that
  -administrators explicitly decide to upgrade to the next minor version of
  -{product-title}. Upgrade channels control only release selection and do not impact the version of the cluster that you install; the `openshift-install`
  -binary file for a specific version of {product-title} always installs that version.
  +In {product-title} 4.1, Red Hat introduced the concept of channels for recommending the appropriate release versions for cluster upgrades. By controlling the pace of upgrades, these upgrade channels allow you to choose an upgrade strategy. Upgrade channels are tied to a minor version of {product-title}. For instance, {product-title} 4.7 upgrade channels will never include an upgrade to a 4.8 release. This strategy ensures that administrators explicitly decide to upgrade to the next minor version of {product-title}. Upgrade channels control only release selection and do not impact the version of the cluster that you install; the `openshift-install` binary file for a specific version of {product-title} always installs that version.
   
   ifndef::openshift-origin[]
   {product-title} {product-version} offers the following upgrade channels:
  
positive.code: [discrete]
  == candidate-{product-version} channel
  
  The `candidate-{product-version}` channel contains candidate builds for a z-stream
  ({product-version}.z) release.
  Release candidates contain all the features of the product but are not supported. Use release candidate versions to test feature acceptance and assist in qualifying the next version
  of {product-title}.
  A release candidate is any build that is available in the candidate channel, including ones that do not contain link:https://semver.org/spec/v2.0.0.html#spec-item-9[a pre-release version] such as `-rc` in their names.
  After a version is available in the candidate channel, it goes through more quality checks. If
  it meets the quality standard, it is promoted to the `fast-{product-version}` or `stable-{product-version}` channels.
  Because of this strategy, if a specific release is available in both the `candidate-{product-version}` channel and in the `fast-{product-version}`
  or `stable-{product-version}` channels, it is a Red Hat supported version.
  The `candidate-{product-version}` channel can include release versions from which there are no recommended updates in any channel.
  
  You can use the `candidate-{product-version}` channel to upgrade from a previous minor version of
  {product-title}.
  
  [NOTE]
  ====
  Release candidates differ from the nightly builds. Nightly
  builds are available for early access to features, but updating to or from nightly
  builds is neither recommended nor supported. Nightly builds are not available in
  any upgrade channel. You can reference the {product-title}
  ifdef::openshift-origin[]
  link:https://origin-release.apps.ci.l2s4.p1.openshiftapps.com/[release statuses]
  endif::[]
  
negative.code: * {product-version}.3
  * {product-version}.4
  
  The service recommends only upgrades that have been tested and have no serious issues. It will not suggest updating to a version of {product-title} that contains known vulnerabilities. For example, if your cluster is on {product-version}.1 and {product-title} suggests {product-version}.4, then it is safe for you to update from {product-version}.1 to {product-version}.4. Do not rely on consecutive patch numbers. In this example, {product-version}.2 is not and never was available in the channel.
  
  ifndef::openshift-origin[]
  Update stability depends on your channel. The presence of an update recommendation in the `candidate-{product-version}` channel does not imply that the update is supported. It means that no serious issues have been found with the update yet, but there might not be significant traffic through the update to suggest stability. The presence of an update recommendation in the `fast-{product-version}` or `stable-{product-version}` channels is a declaration that the update is fully supported while it is in the channel. While releases will never be removed from a channel, update recommendations that exhibit serious issues will be removed from all channels. Updates initiated after the update recommendation has been removed might not be supported.
  
  Red Hat will eventually provide supported update paths from any supported release in the `fast-{product-version}` or `stable-{product-version}` channels to the latest release in {product-version}.z, although there can be delays while safe paths away from troubled releases are constructed and verified.
  endif::openshift-origin[]
  
  ifdef::openshift-origin[]
  The presence of an update recommendation in the `stable-4` channel is a declaration that the update is fully supported while it is in the channel. While releases will never be removed from the channel, update recommendations that exhibit serious issues will be removed from the channel. Updates initiated after the update recommendation has been removed might not be supported.
  endif::openshift-origin[]
  
  ifndef::openshift-origin[]
  [discrete]
  == Fast and stable channel use and strategies
  
  The `fast-{product-version}` and `stable-{product-version}` channels present a choice between receiving general availability releases as soon as they are available or allowing Red Hat to control the rollout of those updates. If issues are detected during rollout or at a later time, upgrades to that version might be blocked in both the `fast-{product-version}` and `stable-{product-version}` channels, and a new version might be introduced that becomes the new preferred upgrade target.
  
  Customers can improve this process by configuring pre-production systems on the `fast-{product-version}` channel, configuring production systems on the `stable-{product-version}` channel, and participating in the Red Hat connected customer program. Red Hat uses this program to observe the impact of updates on your specific hardware and software configurations. Future releases might improve or alter the pace at which updates move from the `fast-{product-version}` to the `stable-{product-version}` channel.
  endif::openshift-origin[]
  
  [discrete]
  == Restricted network clusters
  
  If you manage the container images for your {product-title} clusters yourself, you must consult the Red Hat errata that is associated with product releases and note any comments that impact upgrades. During upgrade, the user interface might warn you about switching between these versions, so you must ensure that you selected an appropriate version before you bypass those warnings.
  
  ifndef::openshift-origin[]
  [discrete]
  == Switching between channels
  
  Your cluster is still supported if you change from the `stable-{product-version}` channel to the `fast-{product-version}` channel. Although you can switch to the `candidate-{product-version}` channel at any time, some releases in that channel might be unsupported release candidates. You can switch from the `candidate-{product-version}` channel to the `fast-{product-version}` channel if your current release is a general availability release. You can always switch from the `fast-{product-version}` channel to the `stable-{product-version}` channel, although if the current release was recently promoted to `fast-{product-version}` there can be a delay of up to a day for the release to be promoted to `stable-{product-version}`. If you change to a channel that does not include your current release, an alert displays and no updates can be recommended, but you can safely change back to your original channel at any point.
  endif::openshift-origin[]
  