Microsoft has released Exchange 2000 Service Pack 3. Thanks DosFreak.
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Release notes
Exchange 2000 Service Pack 3 (SP3) is a cumulative service pack that provides interoperability with Microsoft Windows .NET Server Domain Controllers, fixes to customer-reported issues, and updates based on the Microsoft Trustworthy Computing Initiative. You should download and install Exchange 2000 Server SP3 on all servers running Exchange 2000.Read more
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Release notes