This topic discusses the ability of Office Communications Server 2007 R2 clients to coexist and interact with clients from earlier versions of Office Communications Server.

There are two types of client compatibility, as follows:

Multiple points of presence (MPOP): the ability of a single user to sign in to an Office Communications Server 2007 R2 server with multiple clients
Interoperability: the ability to interact with another user who is signed in using a different client type, or an earlier version of the same client

This topic also discusses the compatibility of Office Communicator 2007 R2 with various versions of Microsoft Office, Exchange Server, Windows, and with selected public instant messaging clients.

Planning for Compatibility

During migration, users with Office Communicator 2007 installed can sign in to an Office Communications Server 2007 R2 server, and interact with Office Communicator 2007 R2 clients. However, they will not have access to the new Office Communications Server 2007 R2 features.

To ensure that your organization’s migration to the new Office Communications Server 2007 R2 clients goes smoothly, consult the following topics:

Migration overview: Migration from Office Communications Server 2007documentation and Migration from Live Communications Server 2005documentation
Client migration: Phase 10: Update Client Softwarein the Migration from Office Communications Server 2007 documentation and Phase 8: Update Client Softwarein the Migration from Live Communications Server 2005 documentation
New features: Office Communicator Enhancementsin the New Client Features documentation

Note:
To coexist and interact with Office Communications Server 2007 R2 clients, earlier client versions must have the most current updates installed.

Compatibility among Office Communications Server 2007 R2 Clients

All Office Communications Server 2007 R2 clients can interoperate with other Office Communications Server 2007 R2 clients.

Most Office Communications Server 2007 R2 clients also support the multiple points of presence scenario, with the following exceptions:

Office Communications Server 2007 R2 Attendant users cannot log on at the same time by using Office Communicator 2007 R2 Phone Edition, the 2007 R2 release of Communicator Mobile for Windows Mobile, and the 2007 R2 release of Microsoft Office Communicator Web Access.
2007 R2 release of Communicator Mobile for Windows Mobile users cannot be signed in on two mobile devices at the same time.

Multiple Points of Presence with Previous Client Versions

The following table describes which client versions are supported when a single user is signed in to an Office Communications Server 2007 R2 server at multiple locations.

Current Client Version	Previous Client Versions Supported (with required updates)
Office Communicator 2007 R2	Office Communicator 2007 Office Communicator 2007 R2 Phone Edition 2007 release of Office Communicator Mobile
2007 R2 release of Office Communicator Mobile for Windows Mobile	Office Communicator 2007 Office Communicator 2007 Phone Edition
Office Communicator 2007 R2 Phone Edition	Office Communicator 2007
Office Communications Server 2007 R2 Attendant	Office Communicator 2007

Interoperability with Previous Client Versions

The following table shows which client versions can interact with Communicator 2007 R2 on an Office Communications Server 2007 R2 server.

Client Interoperability on Office Communications Server 2007 R2

Current Client Version	Previous Client Versions Supported (with required updates)
Office Communicator 2007 R2	Office Communicator 2007 Office Communicator 2007 Phone Edition 2007 release of Office Communicator Mobile 2007 release of Office Communicator Web Access Office Communicator 2005 (basic presence and IM only)
2007 R2 release of Office Communicator Web Access	Supports interoperability with the same clients as Communicator 2007 R2, above
2007 R2 release of Office Communicator Mobile for Windows Mobile	Supports interoperability with the same clients as Office Communicator 2007 R2, above
Office Communicator 2007 R2 Phone Edition	Office Communicator 2007 Office Communicator 2007 Phone Edition 2007 release of Office Communicator Web Access Office Communicator 2005 (basic presence and IM only)
Office Communications Server 2007 R2 Attendant	Supports interoperability with the same clients as Office Communicator 2007 R2 Phone Edition, above

Communicator 2007 R2 Compatibility

This section discusses the compatibility of Office Communicator 2007 R2 with various versions of Microsoft Office, Exchange Server, Windows, and selected public instant messaging clients.

Microsoft Office

The following table describes the Office Communicator 2007 R2 features that are supported by various versions of Microsoft Office.

Communicator 2007 R2 and Microsoft Office compatibility

Microsoft Office Version	Comments
Office 2000	Not supported
Office XP SP3	Contacts No presence menu—INFO line only
Office 2003 SP3	Access presence menu Make voice calls Reply to IMs Search folders and notifications
Office 2007 SP1	View presence button Access presence menu Reply with IM or conference Tagging Contextual data

Exchange Server

The following table describes Office Communicator 2007 R2 support for various versions of Exchange Server. Office Outlook must also be installed on the client computer to handle Extended MAPI calls.

Communicator 2007 R2 and Exchange Server Compatibility

Exchange Server Version	Communicator 2007 R2 Support
Exchange Server 5.5	Not supported
Exchange 2000 Server	Extended MAPI only
Exchange Server 2003	Extended MAPI only
Exchange Server 2007 SP1	Free/Busy information and working hours are available only through Exchange Web Services Public folders are optional in Exchange Server 2007

Windows

The following table describes Office Communicator 2007 R2 compatibility with various versions of Windows.

Communicator 2007 R2 and Windows compatibility

Windows Version	Communicator 2007 R2 Support
Windows Vista 32-bit operating system	Supported
Windows Vista 64-bit operating system	Supported in Windows on Windows 64 mode
Windows XP Professional with Service Pack 2 (SP2) or greater	Supported
Windows 2003 Server SP2 or greater	Supported
Windows 2000 SP4	Not supported

Public Instant Messaging Clients

Communicator 2007 R2 supports IM and basic presence when communicating with the following public instant messaging clients:

Live Messenger
AIM
Yahoo!
Messenger for Mac 7

Presence states are filtered to those supported by the public IM client.