While architecturally Exchange 2007 and 2010 do not require you to deploy public folders, the answer to this question...
varies based on two factors: if anyone in the organization still uses the public folders and if there are any legacy Outlook clients running that depend on public folders.
To determine if anyone still uses the Exchange public folders, harvest some statistics on them. Since you are migrating from Exchange 2007 to Exchange 2010, use the Get-PublicFolderStatistics cmdlet in the Exchange Management Shell to find folder sizes and last logon times.
In the case of Exchange 2010 legacy client in Outlook 2003, migrate public folder systems to continue to support the clients' free busy publishing and offline address book downloads. To verify that you have legacy clients, identify any clients that connect to Exchange Server: Run the Get-LogonStatistics cmdlet from each Mailbox server and then filter for UserName, ClientVersion and LastAccessTime. Look for any client version 11.0.8303.0 (Outlook 2003 SP3) or lower. Version 12.0.4518.1014 (Outlook 2010 RTM) and higher are not considered legacy for Exchange 2010.
To determine if anyone still uses public folders, you can perform a scream test: Dismount the public folder database and see if anyone complains. But I don't recommend that as the best solution to your problems. Exchange 2010 has auditing tools that help you track end-user behavior better.
If you have any doubts, migrate Exchange public folders anyway, and then decide whether to keep them after properly decommissioning your Exchange 2007 servers. You'll avoid inadvertently removing your public folder databases and hierarchy. Tools like the Exchange Deployment Assistant prove helpful during this process.
To automate adding the replicas and then rehoming the folders from Exchange 2007 to 2010, use the scripts -- AddReplicaToPFRecursive.ps1 and Moveallreplicas.ps1 -- included in the Scripts directory on the Exchange 2007 and 2010 servers.
About the author:
Richard Luckett is a consultant and instructor specializing in messaging and unified communications. He's been a certified professional with Microsoft since 1996 and has 20 years of experience in the public and private sectors. Luckett is a Microsoft Certified Trainer with more than 15 years of training experience with the Microsoft product line and received the Exchange MVP award in 2006, 2007 and 2008. He's also an expert in deploying and integrating Exchange Server and Lync Server. He leads the Microsoft training and consulting practice at LITSG.
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