Below is a list of frequently asked questions about the DST 2007 rule changes as they relate to Exchange Server.
Q: What versions of Exchange Server require updates?
A: Exchange Server 2003, Exchange 2000 Server (including Exchange 2000 Server Conferencing Server), and Exchange Server 5.5.
Q: What versions of Outlook require updates?
A: Outlook 2003, Outlook 2002, and Outlook 2000.
Q. Why does Exchange Server require an update?
A. Exchange Server 2003, Exchange 2000 Server, and Exchange Server 5.5 use a publicly documented technology called CDO (Collaborative Data Objects) to manage calendars. CDO uses enumerators to map its time zone information so that it does not need to query the operating system each time it needs time zone information. Outlook is also a consumer of this technology, as is Outlook Web Access, the Lotus Notes Connector, and the GroupWise connector. CDO is also used by many third-party applications.
Q: Knowledge Base article 926666 states that "Collaboration Data Objects (CDO)-based programs such as Outlook Web Access depend on separate internal time zone tables. This update modifies these internal time zone tables to match the DST 2007 changes in the time zone settings." Does a CDO-based calendar item always use these separate internal time zone tables?
A: It depends on the behavior of the application. Time zone tables are stamped on recurring calendar items during creation, and they may be updated if the recurrence is changed. If a CDO-based application created the calendar item, the time zone rules stamped on the item will match the CDO time zone tables. If Outlook creates the calendar item, the time zone rules stamped on the item will match the operating system time zone rules.
Q: If I create an appointment in Outlook Web Access, but always reference and view it in Outlook 2003 or Outlook 2007, will it now use my operating system time zone rules in Outlook, or will it use the CDO-based time zone rules?
A: All applications interpret calendar items using the time zone rules stamped on the item. Because the item was created by Outlook Web Access, all subsequent viewings by any application interpret the calendar item based on the time zones stamped on the item by Outlook Web Access (assuming the recurrence isn’t updated by another application at a later point in time).
Q: Will Outlook users have correct time zone settings for their calendars if their Exchange server is not updated?
A: Outlook does not require updates on the Exchange server; it only requires the client operating system update. Visit Prepare Outlook calendar items for daylight saving time changes in 2007 for more information about updating Outlook.
Q: Will Outlook Web Access users have correct time zone settings for their calendars if their Exchange server is not updated?
A: No, items will be one hour off during the affected time periods (March 11-April 1 and October 28-November 4). Furthermore, in a mixed environment some of your calendar items would be off and some wouldn’t. This situation would be very confusing for end users, and it would negatively affect productivity. Each item would have to be independently verified, which is impractical in most organizations.
Q: Instead of applying updates to the systems, will changing the time zone temporarily for the one-hour difference using group policy or some other means correct problems with calendar time zone settings?
A: This approach might work for some situations, but it won't work for all situations. Each item would have to have to be independently verified, which is impractical in most organizations.
Q. What does the Outlook Data Update tool do?
A: There are two aspects to DST rule change: one with the CDO platform and one with the actual data stored by Outlook. CDO always uses its own internal table of time zone definitions. The CDO hotfix updates the CDO binaries with the new time zone information. The issue with the actual data in appointments relates to the fact that single-instance appointments are at the time based on wrong Coordinated Universal Time (UTC), and recurring appointments have the wrong time zone data. In both cases, the time zone information is determined by the application that created the appointment and the time zone rules in use by that application at the time the appointment was created. The Outlook Data Update tool is intended to update data in the Outlook store to correctly reflect the new time zone rules. The Outlook Data Update tool cannot be run without user intervention. It must be downloaded from the Microsoft Download Center and run through explicit user interaction or a script that launches it under the user’s security context.
Q: What is the Exchange Server Calendar Update tool?
A: This is a server-side form of the Outlook Data Update tool that is intended for administrators. This tool automatically updates client mailboxes without any user interaction. The Exchange Server tool allows you to apply the time zone update in silent mode to a set of specific mailboxes on the Exchange server. Because the update is silent, the end user will not have a chance to uncheck appointments that do not need updating. As might be expected, the Exchange tool only works on server-side calendars. All local calendars must be updated by using the Outlook tool.
Q: How is the target time zone reflected in Outlook items?
A: Single-instance appointments are stored in UTC. The UTC time at which they are stored is determined by the computer used to create the appointments. Outlook 2007 can display this time zone information. In versions of Outlook prior to Outlook 2007, there is no indication of the time zone in which an appointment was created. Recurring appointments have the full time zone definition embedded in their data. In other words, the appointment itself understands exactly what the time zone definition and DST transition dates for it should be.
Q: Why are the tools called "Time Zone Data Update tool" rather than referring to the DST 2007 update specifically?
A: The tools have a generic name because they can move appointments between any two time zones. In the case of the DST 2007 change (or any other modification to time zone rules), the tool is moving appointments from the old versions of the modified time zones to the new versions. If the tool notices that there are new rules for a given time zone, it can automatically try to transition any appointments that are affected by the change into the updated time zone. There are two cases:
- Recurring appointments In this case, the appointment item has the time zone definition embedded in it, so the tool compares that time zone definition to the updated time zone definition. If they do not match, the tool rewrites the appointment with the updated time zone information.
- Singe-instance appointments Items created using versions of Outlook prior to Outlook 2007 do not contain time zone information; therefore, the tool cannot determine whether or not these items need updating. The tool currently assumes that any single-instance appointments in the affected time period were generated using the old time zone rules and offers to update them. If the user has created single-instance appointments in the changed period of time after applying the operating system hotfix that updates the time zone definitions, but before running the tool, then they will need to be careful to tell the tool not to update them (the tool offers to show them a list of all appointments that are thought to need updating and allows the user to uncheck any of those appointments to keep them in place). Because single-instance appointments do not contain any time zone information, those single-instance appointments that were targeted at an unaffected time zone but happen to fall within the affected dates of the time zone that has been modified will also be identified by the tool as requiring update.
Q: Do the time zone updates affect deferred delivery of messages if some or all of the updates are not applied?
A: Deferred delivery is based on local time, so it is unaffected.
Q: Are Task items affected by the time zone updates?
A: Task items use a time and not a date as the reminder. When the Data Update tool is used to update a calendar, it also processes the reminders folders and updates any items that need updating.
Q: When should I run the Data Update tools?
A: The Data Update tools can be run manually at the discretion of the end user or administrator after the operating system time zone updates have been installed. It is preferable to run the Data Update tools as close to the time as possible at which the operating system time zone updates are applied to all computers because that minimizes the likelihood of having single-instance appointments created after the operating system time zone update was applied but before the Data Update tool was run.
Q: If I only run Outlook 2007, do I still need to run the Data Update tool after applying the operating system updates?
A: Because Outlook 2007 has the updated time zone rules already embedded in it, you are not required to manually run the tool (nor use the Change Calendar Time Zone feature of Outlook 2007). After the operating system updates are installed, Outlook 2007 automatically detects that the operating system's time zone definition has changed, and it automatically prompts the user to update the affected items. To minimize the impact to the end user, the update process in Outlook 2007 runs at a random time between 1 and 7 days after the system’s time zone definition changes (not the time at which the changes takes effect). On Windows Vista, this change occurred on January 1, 2007, which was when Windows Vista clients automatically transitioned to the DST 2007 rules. On other Windows operating systems, this change will occur after the operating system updates have been applied.
Q: Why doesn’t the Data Update tool update all of my affected appointments?
A: The tool only updates appointments for which the user is the organizer and then automatically sends updates for those appointments to all other attendees. A calendar will not be 100 percent accurate until the calendar’s owner has run the Data Update tool and all other users that organized meetings to which the calendar’s owner was invited have also run the tool. This is another fundamental reason why you should treat all potentially affected appointments as suspect and verify the times themselves and with any other invitees.
Q: What happens if I run the Data Update tool multiple times?
A: The tool correctly stamps the appointments it updates with the time zone information in which they were encoded. Therefore, it is generally safe to run the tool multiple times because it will see all of the appointments that were updated and ignore them. Note that if the user explicitly asks the tool to ignore a set of appointments (for example, single-instance appointments that are targeted at a different time zone or that the user created after updating time zone rules but before running the time zone update tool), the tool will continue to discover those appointments in future runs and the user will have to explicitly ignore those appointments on each run.
Q: What happens if my end users use multiple computers, and some of those computers do not have the updates applied?
A: After the Data Update tool has been run from a computer that has the DST updates applied, be careful about using computers without the updates because appointments will be created with out-of-date time zone information and you will have to run the tool again to update them.
Q: Will there ever be an automated way of running the Outlook Data Update tool?
A: In addition to the Exchange version of the tool that can be run by the administrator on behalf of users, you can configure the tool to run silently on user computers using login scripts using regular mode (where the user is prompted) or using quiet mode (where the calendar is updated without user intervention).
Q: Are there plans to make the tool deployable via Windows Server Update Services (WSUS)?
A: No. The tool cannot be deployed or launched through WSUS because it requires that it be run under the user's security context.
Q: Microsoft Office XP, which includes Outlook 2002, entered into its Extended Support Phase on July 12, 2006. Will the update tool work for Outlook 2002?
A: The Outlook Data Update tool is independent of the version of Office. It is being tested with and will operate on Outlook 2003, Outlook 2002, and Outlook 2000.