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Export what config you can (profiles / test cases / template sets) for later use, take screenshots of notification config screens, mailbox handler config etc.
JEMHC must be uninstalled prior to migration, otherwise the migrated Jira will still point to the original (typically USA) app location. Uninstalling JEMHC also prevents mail retrieval ahead of the migration. We retain that data for 30days so you could reinstall JEMHC if the migration failed and a rollback is needed - no JEMHC data loss will occur if this is done within 30days!
After migration, reinstall JEMHC to get a fresh install in the target region.
Import saved profiles / test cases / template sets if required
Reconfigure all inbound/outbound connections, handlers and notification mappings
When changing regions ensure you update any firewall rules you have in place, as we have different outbound IP addresses (2 for multi-AZ) for each geographical region, see EU and DE app data location IP addresses to allow .