We are running exchange Version: 6.5.7638.1 we would like to know if we can upgrade our clients from Outlook 2000 to any new version of Outlook without any trouble ...?

No problems going backwards. So Outlook 2010 will go back to Exchange 2003 without any issues. Going forwards (so Exchange is newer than Outlook), normally ok within one or two versions. The Technet documentation for the version of Exchange will state what is supported and what isn't. Of course you will not get the full feature-set of the later versions of Outlook. There are things in Outlook 2010 that require Exchange 2010 for example. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

On Tue, 26 Apr 2011 20:25:23 +0000, Garth at Allsite IT wrote: >We are running exchange Version: 6.5.7638.1 we would like to know if we can upgrade our clients from Outlook 2000 to any new version of Outlook without any trouble ...? Yes, you can. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Hi, According the below doucment, 6.5.7638 is Microsoft Exchange Server 2003 SP2. http://social.technet.microsoft.com/wiki/contents/articles/exchange-server-and-update-rollups-builds-numbers.aspx Of course ,Exchange 2003 support any version of Outlook later 2000.Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.