We just upgraded from Exchange 2007 RTM to Exchange 2007 SP1 yesterday morning and I’m happy to say that the upgrade went very smoothly. It took about 20 minutes.

Here are some things to consider:

1. Install .NET Framework 2.0 SP1 before upgrading. This may not be required but Microsoft recommends it.
2. If you have more than one Exchange server, Microsoft recommends that you upgrade the servers running the Mailbox server role last. Upgrade your servers in the following order:
   1. Client Access servers
   2. Unified Messaging servers
   3. Hub Transport servers
   4. Edge Transport servers
   5. Mailbox servers
3. If you have third party software running on the Exchange server, stop the services/processes for those software before running the SP1 installation (e.g. antivirus, Backup Exec Remote Agent, etc.).
4. Check the compatibility of other software that use/connect to the Exchange server. Some examples:
   1. BlackBerry Enterprise Server. We have BES version 4.1.3 and I can confirm that this version works with Exchange 2007 SP1. E-mails, contacts, calendar, tasks, notes, Out-of-Office are synchronizing properly. No issues so far. I’m assuming that higher versions would also work.
   2. Symantec Backup Exec 11d. Make sure that you upgrade the Exchange Management Tools on the server running Backup Exec to Service Pack 1 as well (and install other patches for Exchange that you have installed on your Exchange server) or you may get this error:Unable to complete the operation for the selected resource using the specified options. The following error was returned when opening the Exchange Database file: ‘-514 The version of the log file is not compatible with the ESE version.’ Go here for more details: http://seer.entsupport.symantec.com/docs/289970.htm.
5. Read the release notes.

Update Rollup 1 for Exchange Server 2007 Service Pack 1 (KB945684) was also just released three days ago and you may want to install this as well.