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The Include Bitbucket for Confluence app supports both, Bitbucket Data Center and Cloud. You can choose to migrate to Bitbucket Cloud when migrating to Confluence Cloud as well, or keep the existing Bitbucket Data center Center instance.
In case you keep the files your repositories on Bitbucket Data Center: it needs to be accessible via HTTPS on the public internet.
3. Configure Access to Bitbucket in Confluence Cloud
Configure access to Bitbucket in Confluence cloudCloud:
Configure Access to Bitbucket Cloud
Configure Access to Bitbucket Data Center
4. Migrate using the Confluence Cloud Migration Assistant
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