Note: Doc team updates the current version of the documentation and the
two previous versions (n-2), but we address *only high-priority, or
customer-reported issues* for -2 releases in support.
Describe the changes in the doc and link to your dev story:

1. - [x] Mandatory: Add the required version to the Fix version/s field.

2. - [x] Mandatory: Choose the type of documentation change or review.

• [ ] We need to update to an existing topic

• [x] We need to add a new document to an existing section

• [ ] We need a whole new section; this is a function not
  documented before and doesn't belong in any current section

• [ ] We need an Operator Advisory review and approval

• [ ] We need a z-Stream (Errata) Advisory and Release note
  for MCE and/or ACM

3. - [x] *Mandatory: *Use the following link to open the doc and find where the
documentation update should go. Note: As the feature and doc is
understood and developed, this placement decision may change:

• Published doc: https://docs.redhat.com/en/documentation/red_hat_advanced_cluster_management_for_kubernetes/2.12/html/install/installing#upgrading
• Source: https://github.com/stolostron/rhacm-docs/blob/2.13_stage/install/upgrade_hub.adoc

4. - [ ] Mandatory for GA content:

• [x] Add steps, the diff, known issue, and/or other important
  conceptual information in the following space:
  • In ACM 2.13, we introduce the ability to perform skip level upgrades on odd versions of acm starting with 2.11 and even versions of mce starting with 2.6. This is to introduce the intention of making sure users/customers are able to upgrade from supported versions of acm/mce as there will be a scenario with eus support that users/customers would otherwise have to upgrade to an unsupported version first (2.11 supported to 2.12 unsupported for example) because 2.11 is an eus version that will have a longer support than 2.12

• [x] *Add Required access level *(example, *Cluster
  Administrator*) for the user to complete the task:
  • OpenShift Container Platform administrator 

• [x] Add verification at the end of the task, how does the user
  verify success (a command to run or a result to see?)
  • To verify an EUS upgrade has been performed successfully, the csv version is at 2.13. The mch cr instance should also have 2.13 value under status.currentVersion matching 2.13 value under status.desiredVersion. Check for the same thing in the mce cr stance with the value of 2.8 in the yaml

• [x] Add link to dev story here: https://issues.redhat.com/browse/ACM-15717

5. - [ ] Mandatory for bugs: What is the diff? Clearly define what the
problem is, what the change is, and link to the current documentation. Only
use this for a documentation bug.