You can use Deep Clone as a tool to migrate issues to another project without data loss. Migrating issues is possible between all Jira project types (company-managed, team-managed, software, JSM).
A benefit of using Deep Clone for your project migration is, that clones are created from the original issues. The orignal issues remain unchanged in the original project.
To migrate issues from one project to another you need to perform a Bulk Clone.
Hints and tricks for migrating issues between projects
Make sure that all issue fields you want to clone are also configured in the target project. The spelling of the field must correspond. (Components and versions can be created automatically by Deep Clone while cloning)
Cloning is easier if fields are not required in the target project while cloning.
Consider creating an interim workflow for your target project, when you want to clone the issue statuses.
Consider disabling notifications in the notification scheme of the target project, to avoid too many notifications when bulk cloning.
In the default settings we add the Prefix “CLONE -” to every clone that is created. Make sure to uncheck that item when you want to prevent that.
In the default settings we add a “clones” issue link between the clone and the original issue. Make sure to uncheck that item when you want to prevent that.
Company-managed (classic) Jira projects can be cloned with Deep Clone for Jira. Here you can find more details about the Project Clone feature.