Store.IsConversationEnabled Property (Outlook)
Returns a Boolean value that is True if the store supports Conversation view. Read-only.
A store supports Conversation view if the store is a POP, IMAP, or PST store, or if it runs a version of Microsoft Exchange Server that is at least Microsoft Exchange Server 2010. A store also supports Conversation view if the store is running Microsoft Exchange Server 2007, the version of Outlook is at least Microsoft Outlook 2010, and Outlook is running in cached mode.
If a store supports conversations, calling the GetConversation method of an item in the store returns a Conversation object for the item. If the store does not support conversations, GetConversation returns Null (Nothing in Visual Basic) for items in the store.