Hi, We have Exchange Server 2003 and various editions of Office ranging from Office 2000 through to Office 2010 which we are in the process of migrating to, along with Windows 7. We currently use Windows XP SP3 as our primary OS on client devices and last year when the clocks changed, a large number of our users, mainly the execs, had issues with calendar entries being out of sync by 1 hour. We applied a timezone fix to a number of individual PCs and had varying results - for some this fixed the problem but for others it made no difference. I understand that this is related to time-zone changes and many articles i have read suggest that the CDO.DLL needs to be updated on the Exchange 2003 server (we also have a BES 5 server, and this too needs an updated CDO.DLL). My research online has suggested that the CDO.DLL is not used by Office 2010. I have been trying to find out whether or not the issue causing the calendars to be out of sync is caused by the Exchange server requiring an update, the Exchange server and the clients (2003 and earlier) needing an update, the Exchange server, BES server and the clients (2003 and earlier), or just the clients (again 2003 and earlier). Whilst we are in the process of migrating to Windows 7 and to Office 2010, it could be some time before the entirety of the organisation migrates, although in making that statement, the Exec will certainly be the very first to migrate to Office 2010 which is why my question focuses on Exchange 2003 / Office 2010. We have no plans at this point to upgrade Exchange from 2003 to 2010 - regardless of the new functionality this may provide when used alongside office 2010. We want to ensure that our execs do not have a repeat of this issue that plagued the organisation last year and i have been tasked with investigating what is required in order to mitigate recurrence. If we leave our exchange server running the older CDO.DLL, and update to Windows 7 and Office 2010, will we still have issues with the calendar entries being 1 hour out of sync or do we need to apply all available updates to the Exchange 2003 server - specifically the time zone hotfixes and updated CDO.DLL and update the DLL on the BES server too? I work at a bank and although we have the budget to upgrade Exchange to 2010, i believe this will only happen if it is an absolute requirement or if there is a definitive business need. If anyone out there is able to shed some light on this, i would be most appreciative. All of the articles out there that i've managed to find refer to the use of Exchange 2007 and OFfice 2010, not Exchange 2003 and Office 2010. Thanks in advance for any help you might be able to give me on this. Steviejoe

Hi Stevie, Event though we upgrade to Exchange 2010, the DST update should be applied on all Exchange servers, BES servers, and client computers. Besides, the hotfix requires a reboot to take effect. Fiona Liao TechNet Community Support

Hi Fiona, Thanks for your reply. Did you need to update the CDO.DLL file on any of the servers / client PCs or is this not necessary? Best regards, SteviejoeSteviejoe