Understanding Meeting Updates

Since working with the Outlook calendar, and more specifically with meetings, it is very likely that the majority of us have encountered situations in which updates to meetings are not triggering the same type of message.

And what I mean by this is that depending on the type of changes that we make to a meeting, this will generate either an informational or a full update, and the information will be changed or not, accordingly, on the attendee’s calendar.

As I have discovered a good bit of documentation on this topic, I think the below article can be useful in either troubleshooting calendar issues or in understanding the expected behavior in such scenarios.

In earlier versions of Outlook, you could easily run into one or more of the following problems when sending a meeting update:

• Invitees have to reaccept meetings unnecessarily.
• Attendees do not see anything different with the meeting and they delete the request thinking they have already dealt with it.
• The invitee or recipient list does not handle duplicate entries and distribution lists elegantly. Consequently, invitees may receive cancellations and updates at the same time.
• Attendees do not always have an up-to-date invitee list because updates are not sent correctly.

Starting with Outlook 2007, meeting updates are classified as one of two types: a full update or an informational update.

The difference between these two is worth discussing, as Outlook uses each type in a very specific scenario. Basically, this is the topic for this blog, with a focus on describing the scenarios that trigger either a full or informational update. Additionally, you will learn how to make Outlook send a specific type of update, depending on the meetings properties that you want to change.

What is a full update?

A full update is practically a new meeting invitation to the same event, replacing the old properties with the new ones. Full updates are sent when one or more of the following properties are changed:

• Start Date/Time
• End Date/Time
• Recurrence

A Full update has the following characteristics:

• An organizer must send out the update. They cannot change and then save certain properties on the meeting without sending an update.
• The attendee must reaccept the updated meeting.
• If the receiving attendee does not have the meeting on their Calendar, the meeting is created on the Calendar (as if it is a new meeting request).
• Changes to the meeting are highlighted in color in the attendee’s meeting invitation and the public properties on the meeting are overwritten on the attendee’s calendar item.

In a few words, in Outlook 2007 and 2010 you can no longer make critical changes on a meeting without sending an update. For example if you attempt to delete a meeting, the Send Cancellation form automatically appears. You cannot save this change without clicking the Send Cancellation button to send the cancelation email.

When you receive a full update from the organizer, you are requested to respond to the meeting.

What is an Informational update?

An Informational update is an update that does not require any action from the attendee. As the name states, it was designed to simply inform the attendee of specific changes that have occurred on the meeting. Informational updates have the following characteristics.

• The update does not have to be reaccepted by attendees.
• The Free/Busy status of the meeting is unchanged.
• Changes to the meeting are highlighted in color in the attendee’s meeting invitation and the Public properties in the meeting are overwritten on the attendee’s calendar item.
• If the meeting is not on the Calendar of the receiving attendee, the meeting update behaves as a Full meeting update.

 If you receive an informational update and the invite is processed, the required action is clearly spelled out in the message. If you are viewing the message in the Reading Pane, the informational message is clearly highlighted in the invite. The informational message appears in the light blue box in the following image:

If you click the No Response Required button in the Reading Pane, you are notified that your calendar has been updated and the meeting update is automatically deleted.

If you open the invite for an informational update, the Information Bar clearly states that your calendar has been updated and that there is no need to respond to the update.

Please note that the Accept, Tentative, and Decline buttons are available. However, you are not required to respond to the update.

In brief, here is a table describing the properties that can change on a meeting and what kind of update do they trigger:

There are also two types of properties on the meetings: public and private.

Public and private properties of a meeting are properties that exist when a meeting is created. For the most part, as an attendee you can change these properties for any meeting that you have accepted or tentatively accepted. The difference is that any of your previous edits to Public properties are overwritten if the meeting organizer changes any of them and sends you an update to the meeting (regardless of whether it is an informational or full update).

Private properties are those that you can edit on your local copy of the meeting and that will not be changed when the meeting organizer sends you a meeting update.

There is one exception to the above rule, which is the following. Free/Busy status is the only private property that can change but only with a full update:

So whether the attendee makes a change on any of these private properties, they will behave as described above.

A full update will change the free/busy time, whether or not the attendee previously changed it.

The sensitivity and the reminder time are never changed, except if the attendee has not yet accepted the initial meeting request before receiving the update to it.

To exemplify this let's take a scenario with userA as organizer and userB, userC as attendees.

Note: I also used the public property Importance in this scenario.

UserA sends a meeting request to userB and userC with Free/Busy as tentative, private, high importance and 15 minutes reminder.

Both attendees accept the meeting.

UserB leaves the meeting as it is, however userC changes the sensitivity to public, the importance to normal, the free/busy to busy and the reminder to 10 minutes, after which he saves and closes the meeting.

UserA, as organizer, changes the end time, to another half an hour, free/busy to free, reminder to 30 minutes, importance to low and the sensitivity remains to private.

Since the end time was changed, this will trigger a full update. However on the attendees, after reaccepting the meeting we will see the following:

UserB will have the time updated, importance to low, free/busy to free, reminder to 15 minutes and sensitivity to private.

UserC will have the time updated, importance to low, free/busy to free, reminder to 10 minutes and sensitivity to public.

To go a bit further with this topic, there are also some ways of checking if the update received for a meeting was informational or full.

The MAPI property Named Prop Name=0x0026 stamped on the meeting update indicates the type of meeting request or update being sent. You can use MFCMAPI to examine the property.

• Download and install MFCMAPI form the following location:
  http://mfcmapi.codeplex.com/releases/view/73290

Note: You should download the latest version but please use the same bit-version you have in Outlook (32 or 64 bit)

• Open MFCMAPI
• Go to Session -> Logon and Display Store table
• Double-click on the user’s mailbox
• Expand the Root and then
• if the profile is configured in Online mode expand Top of Information Store
• if the profile is configured in Cached mode expand IPM_Subtree
• Right-click on Inbox and select Open Contents Table
• From the window that pops-up locate the item in the top pane. The MAPI Properties of the item are at the bottom pane
• Look at the bottom pane to locate the Named Prop Name 0x0026 property.

 The values for this property are listed in the following table:

Hope this was helpful in understanding and troubleshooting issues of this kind.

Feel free to comment or add any remarks to the topic and keep on outlooking!