Backbone has multiple options for synchronizing user fields (such as assignee and reporter).

The synchronization user needs the 'Assign Issues' permission if you want to map the assignee, and the 'Modify Reporter' permission if you want to map the reporter.

User field mapping options

Ignore unassigned

What does it do?

When ignore unassigned is activated, empty user field values are not synchronized.

For example: user John Doe is synchronized as an assignee from project A to project B. Activating ignore unassigned means that if John Doe is removed as assignee from project A, project B will ignore this because it is a change to an empty field, and John Doe will remain as the assignee in project B.

How do I use it?

Activate the ignore unassigned setting by clicking the Ignore empty values for this user field checkbox:

Fallback user

What does it do?

If you and your synchronization partner have different userbases in your JIRA systems, sometimes the partner might synchronize user values that do not exist in your JIRA userbase. If you assign a fallback user, the field value will automatically fall back to that user if the synchronized user does not exist in your JIRA userbase.

How do I use it?

You can set a fallback user by selecting the Passthrough Field Value Mapping setting, and typing the user's name in the dropdown list on the bottom-right of the screen.

When the synchronization user has the 'Browse Users' permission, you will also get autocompletion in this select. Please see the global permissions inside your JIRA how you can assign them.

User prefix

What does it do?

The user prefix function lets you add or remove prefixes to the start of synchronized user values. This is helpful in cases where your organization has certain naming conventions for internal or external users, for example.

How do I use it?

To configure prefixes, you must first select the Prefixed User Field Value Mapping setting.

Define prefixes to be removed by entering a value in the User prefix to remove box, and define prefixes to be added by entering a value in the User prefix to add box:

In this example, the user John Doe in project A would appear as INT-John Doe in project B.

User to String 

What does it do?

The user to string option lets you map a user field to a custom text string.

How do I use it?

You must map the user field to a text field. The mapping can only be unidirectional, because Backbone doesn't support parsing the user field from the other instance.

In the field mapping configuration, you can enter the text string in the Custom User Format text box:

You can use the following placeholders in the text string:

the user's JIRA display name
the user's JIRA log-in name
the email address associated with the user's JIRA account