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The New Connector is built on the Atlassian Connect framework and has a different data model than the Classic Connector. Hence, you will need to run a self-service export and import, as well as some further configurations.
Prerequisites
You have reviewed Migrating from Classic Connector for Salesforce & Jira server to cloud.
Things to Note
Maintenance window
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Any existing data on the New Connector will be wiped
Performing the migration will destroy any data (if it exists) in the New Connector. It does not remove JIRA data.
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Jira data.