Will the UniqueId of an appointment change if an Exchange Server is migrated from 2007 SP3 to 2013?
According to this post (https://social.technet.microsoft.com/Forums/office/en-US/5a746aa7-ee58-4edd-8a8e-43c501da2242/ews-managed-api-how-unique-is-the-uniqueid-of-an-appointment-item-does-it-survive-a-migration-from?forum=exchangesvrdevelopment), "Your migration from 2007 SP1 (or later) to 2010 will not change the uniqueness of the identifiers."
I would expect that all identifiers would remain unique, but will they change?