Cisco Unity 4.2 -- can we patch that for exchange 2010 support?
This wont be the answer you want so forgive me in advance. The answer is NO. Unity only provides support for Exchange 2010 integration in Unity 5x and 7x at the moment. For both, you need to be at a specific ES release as well as follow a documented set of procedures to get the integration working. You also have to install a MAPI patch because the MAPI protocol was changed in Exchange 2010 (MAPI is the primary protocol by which Unity works and accessing mailboxes on Exchange). Support for Unity 8x is planned but is not official (to my knowledge) yet. There is no plan to support Exchange 2007 or Exchange 2010 integration with Unity 4x. If you're company is moving to Exchange 2010 and you need to provide Unified Messaging then you should upgrade to Unity 7x. If Unified Messaging isn't a hard requirement, you could migrate from Unity to Unity Connection which is a standalone voice messaging solution and works independently of what the corporate mail store is.
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