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Clean up
Remove not used templates, if you are keeping old templates just to have access to that template execution history - it won’t be migrated. That’s why it is better to build some Jira filter or add some new/special label to mark those issuesClean up, again
Migration is a great opportunity to make some adjustments and removal of not used templates. Again remove unnecessary and not used templates.
Data Security in terms of migration
Here you can read about it: https://psc-software.atlassian.net/wiki/spaces/SCHED/pages/1773323/Data+Security+and+Privacy+Statement#Migration-from-server-to-cloud-concerns