Exchange 2007 includes all the VSS features in Exchange Server 2003, and the new ability to restore Exchange data to an alternative location. In Exchange Server 2003, the Exchange VSS Writer component did not enable retargeting VSS restores to a location other than their original path. In Exchange 2007, you can restore VSS backups to alternative locations.

Exchange 2007 no longer requires the use of public folders for services such as free and busy database and offline address books when using Microsoft Office Outlook Web Access or Office Outlook 2007. Therefore, unless you have a content or application-based need for public folders, you do not have to deploy or maintain a public folder database. If you plan to deploy organizational forms in your organization or if you have Microsoft Office Outlook 2003, you will still need to use public folders.

Exchange 2007 enables administrators to customize messages for size limits and quota overages. Exchange 2007 now provides mailbox and message send limitation settings to Outlook Web Access and Microsoft Outlook. Exchange 2007 also lets you customize these messages to make them more meaningful to the user. For example, you can customize the message to include the limits information, such as the user's current send and mailbox size limits and the current size of their mailbox.

Additionally, two other customizations are now possible:

• The 32 KB rules limit has been increased to a default size of 64 KB per mailbox. The rule limit is now a customizable limit of up to 256 KB per mailbox.
  
• Exchange 2007 includes MAPI as a protocol that can be allowed or disallowed on a per-mailbox basis. Earlier versions of Exchange only allowed administrators to restrict MAPI access at the Exchange store level. Exchange 2007 enables administrators to restrict MAPI access at the mailbox level.
  

The Exchange database architecture has changed in four significant respects:

• The streaming database (.stm) file has been removed from Exchange 2007.
  
• Longer log file names are used, thereby enabling each storage group to generate as many as 2 billion log files before log file generation must be reset.
  
• Transaction log file size has been reduced from 5 MB to 1 MB to support the new continuous replication features in Exchange 2007.
  
• The database page size has increased from 4 KB to 8 KB.