anchor.diff:  ====
   When you update a cluster that contains Red Hat Enterprise Linux (RHEL) worker machines, those workers temporarily become unavailable during the update process. You must run the upgrade playbook against each RHEL machine as it enters the `NotReady` state for the cluster to finish updating.
   ====
  +
   endif::rhel[]
  
positive.code: link:https://access.redhat.com/downloads/content/290/ver=4.5/rhel---7/4.5.4/x86_64/product-errata[in the errata section]
  of the Customer Portal.
  ////
  update link to 4.4 when available
  ////
  
  .Prerequisites
  
negative.code: .Procedure
  
  . From the web console, click *Administration* > *Cluster Settings* and review
  the contents of the *Details* tab.
  . For production clusters, ensure that the *Channel* is set to the correct channel for
  ifdef::within[]
  the version that you want to update to,
  endif::within[]
  