Summary

There is a lot of confusion around this KB with regards to the ticket being raised for customers who receive emails regards to data loss on epic links and parent links, so let me break it down a bit for everyone. Just to give you a backstory, the epic link and parent link on Jira were primed for deprecation. This was to make the entire Jira suite relatable and similar in appearance and functionality. Specifically towards Company-managed vs Team-managed projects.

The product team decided to merge any relationship between a parent-child issue into a field called the "parent" field rather than the whole "Epic Link" or "Parent Link" field.

The "Parent Link" was only available if and only if the instance has an Advanced roadmap. This made understanding the hierarchy level a bit tedious for different vendors alike.  When the merger happens, issues will only have a parent field if they are child issues.

This hierarchy will now be controlled centrally, if and only if you have Advanced roadmaps, you can tweak the hierarchy level above an epic. If you do not have Advanced roadmaps, this option won't be available to you and you will have the standard hierarchy level of
Epic →  Story/Bug/Task →  Sub-task.

Environment

Jira Software Cloud

Diagnosis

After multiple customers reverting back with queries on the earlier KB article, we have planned to update it with FAQs.

Cause

In order to maintain consistency for team-managed projects and company-managed projects, Atlassian has decided to move from epic links and parent links to just the parent field where the customers are confused with the current documentation provided, thereby explaining with FAQs below in the solution.

Solution

What are valid and invalid links?

• A valid link is a relationship that has a parent-child relationship up to 1 level below an epic. E.g Epic -> Story
• An invalid link is a relationship that is more than 1 level above or below an epic or the same level as an epic. E.g. Feature -> Epic or Product -> Initiative -> Epic

Why is a hierarchy level that was created by Advanced Roadmap invalid?
 
The reason you will see this as invalid is that some users were using Epic Link to link a hierarchy that was higher than an epic instead of the "Parent Link" field. This will be determined as an invalid relationship.
This sort of linking won't be possible anymore and you'll get an error if you try to perform such linking.

What does this mean to customers?

• When this change is rolled out [Nov 2022], if the user has an invalid relationship, it will be deleted.
• As long as the relationship is valid, those relationships will be moved automatically to the parent field [2022-2023]. There's no action required by the user.
• If you received an email notification and you do not have an invalid link, just ignore the message. You have nothing to worry about.

I'm worried I have an invalid relationship link.

• Check your issue hierarchy configuration and ensure that hierarchy levels are set correctly. Use the JQL query to ensure that you've not set an invalid link before.

How will I know if they are set correctly?

• On Jira, the hierarchy level flows in this direction Epic →  Standard Issue types → Sub-task e.g. Epic Issuetype →  Story/Bug/Task Issue type →  Sub-task Issue type

Do I change my issue hierarchy?

• Please avoid changing the issue hierarchy if you already have one configured from before. Changing the issue hierarchy may invalidate existing parent and child relationships if you have a hierarchy higher than an Epic.

What's the deal with the JQL search?

• The JQL query is used to search for those issues with the invalid relationship, so once filtered, you can then clear those issues from the epic-link
  field and link them using the link issues feature if you want to maintain any epic relationship which was set wrongly.