In general, you can separately upgrade groups of users to Microsoft Office Outlook 2003 from earlier versions of Outlook and not lose e-mail and other message functionality between users of different versions. Outlook 2003 uses the same MAPI profiles as previous versions of Outlook. However, there are a few format changes introduced in versions of Outlook that might cause backward compatibility or interoperability issues. These few exceptions are described in the following sections.
Outlook 2003 introduces a new Unicode file format for personal folder files (PST files) and offline folder files (OST files). The new format permits larger file sizes (the previous limit of 2 gigabytes (GBs) is eliminated) and allows for storing Unicode-format information. These file format changes might introduce problems if you upgrade to Outlook 2003 and create files with the new format, and then try to share files with someone using an earlier version of Outlook.
The OST file in Outlook 97 version 8.03 is different in later versions of Outlook, including Outlook 2003. When you upgrade to Outlook 2003 from versions of Outlook 97 prior to version 8.03, you must recreate the OST file.
In addition to Rich Text Format (RTF) and plain text (ASCII) format, Outlook 2003, Outlook 2002, Outlook 2000, and Outlook 98 support HTML-based e-mail messages. This format allows users to send messages in HTML format.
Outlook 97 supports only RTF and plain text format, but Outlook 2003 converts and stores HTML in RTF so that Outlook 97 users can read the messages. However, the original HTML might not be displayed correctly in RTF.
Outlook 2003 includes enhanced support for online meetings compared to earlier releases of Outlook. If you have an environment in which users on different versions of Outlook exchange meeting requests, be aware of the limitations outlined below.
In Outlook 2003, you can link a meeting request to a Meeting Workspace. A Meeting Workspace is a Web site that serves as a central point for information and materials relating to an upcoming meeting. There are some limitations when working with Meeting Workspace if some users are on older versions of Outlook. These include the following:
When viewing the meeting invitation as an attendee in an earlier version of Outlook, a user can click on the link in the message body to navigate to the Meeting Workspace. The user’s meeting response (for example, Accept or Decline) is not recorded in the workspace when the user responds from an earlier version of Outlook. Users can optionally navigate to the workspace and manually record their responses in the workspace.
When viewing a Meeting Workspace meeting request as an organizer of the meeting in an earlier version of Outlook, any changes you make will not be reflected in the workspace. You will need to reopen the meeting request in Outlook 2003 and resend it to the meeting attendees to update the workspace.
Outlook 2003 also supports other types of online meetings, hosted by using Microsoft NetMeeting conferencing software, Exchange Conferencing Services, or Microsoft Windows NT Server NetShow™ Services. (NetShow Services could be hosted by a Windows Media 9 server instead.) Online meeting requests made by using the Outlook 2003 NetMeeting or NetShow Services features may appear as in-person meeting requests to Outlook 97, Outlook 98, or Outlook 2000 users.
If your organization includes Outlook 97, Outlook 98, or Outlook 2000 users, and you schedule an online meeting by using Outlook 2003, it is best to identify the meeting format in the content of the message: NetMeeting, Exchange Conferencing Services, or NetShow Services. Otherwise, users may not be aware that the meeting is an online meeting or may be unable to tell which type of online meeting it is.
In addition, if recipients of a meeting request set or activate reminders, this action might not work with online meeting requests in environments involving different versions of Outlook. For example, recipients of meeting requests may see the following message if they attempt to activate a reminder after receiving an online meeting invitation:
“The Reminder for <Subject> cannot be set because its time has passed. Is this OK?”
When you upgrade to Outlook 2003, the Outlook 98 Stationery files are moved to a new location. Outlook 98, Outlook 2000, and Outlook 2002 user signatures are preserved in Outlook 2003.