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If the Bitbucket Server is licensed for more than 2000 user (Datacenter license of Bitbucket), you will need to contact Atlassian, if you're a Partner or reseller, or your Atlassian Partner/reseller for a license. You have to fill in the form in order to receive a Datacenter license. Only Atlassian can create Data Center licenses. The license you can purchase via the Marketplace are only designed for a single server.
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