Log in as a user with the JIRA Administrators' global permission.
Navigate to your project → Settings → Apps → Migrations
Select the fields which you would like to convert.
Optional: you can define a name for the converted secure field.
Press Migrate button to complete the operation.
Please note that the history of the field will not be migrated.
Please note: If the custom field has had contexts for different issue types and some of those contexts were removed from the configuration, it is possible that after the migration to the secure field and adding the removed contexts again, the values of the pre-migrated fields may re-appear in the custom fields (not in the secure fields). A potential solution is to add a global context for the time of migration.
