Topic Last Modified: 2011-05-13

This topic discusses the ability of Microsoft Lync Server 2010 clients to coexist and interact with Microsoft Office Communications Server 2007 clients.

Note:
Lync Server 2010 can coexist with components of either a Office Communications Server 2007 deployment or a Microsoft Office Communications Server 2007 R2 deployment. Concurrent deployment of Lync Server 2010 with both Communications Server 2007 and Office Communications Server 2007 R2 (concurrent deployment of all three versions) is not supported. For details, see Coexistence Scenarios.

There are two types of client compatibility:

Multiple points of presence (MPOP) The ability of a single user to sign in to a server with multiple clients and multiple client versions.
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.

Planning for Compatibility

Important:
In order to fully test the new Lync Server 2010 features during migration, you must ensure that previous client versions have the most recent updates, or hotfixes, installed.

Lync Server 2010 fully supports interoperability among Lync Server 2010 clients.

Most instant messaging (IM), presence, and voice features are also supported when interacting with Communications Server 2007 clients. For details, see the "Lync Server 2010 Interoperability with Previous Client Versions" section later in this topic.

Compatibility among Lync Server 2010 Clients

All Lync Server 2010 clients can interoperate with other Lync Server 2010 clients.

Most Lync Server 2010 clients also support the multiple points of presence scenario—that is, a single user can be signed in at multiple locations—with the following exception:

Microsoft Lync 2010 Attendant users can only be signed in simultaneously with phones running Microsoft Lync 2010 Phone Edition. Simultaneous sign-in with other Lync Server 2010 clients is not supported.

Multiple Points of Presence (MPOP) with Previous Client Versions

The following table describes the client versions that are supported when a single user is signed in to Lync Server 2010 at multiple locations.

Note:
Lync Server 2010 clients cannot sign in to previous server versions.

Client Versions Supported for Sign in from Multiple Locations

Current client version	Client version MPOP support (with required updates)
Microsoft Lync 2010 Microsoft Lync 2010 Attendee	Microsoft Office Communications Server 2007 Microsoft Office Communicator Web Access (2007 release) Phones running Microsoft Office Communicator 2007 Phone Edition Microsoft Communicator for Mac 2011
Microsoft Lync 2010 Attendant	Phones running Microsoft Lync 2010 Phone Edition
Phones running Lync 2010 Phone Edition	Microsoft Office Communicator 2007 Microsoft Communicator for Mac 2011

Current client version

Client version MPOP support (with required updates)

Microsoft Lync 2010

Microsoft Lync 2010 Attendee

Microsoft Office Communications Server 2007

Microsoft Office Communicator Web Access (2007 release)

Phones running Microsoft Office Communicator 2007 Phone Edition

Microsoft Communicator for Mac 2011

Microsoft Lync 2010 Attendant

Phones running Microsoft Lync 2010 Phone Edition

Phones running Lync 2010 Phone Edition

Microsoft Office Communicator 2007

Microsoft Communicator for Mac 2011

Lync Server 2010 Interoperability with Previous Client Versions

This section discusses Lync Server 2010 interoperability support for clients that shipped with Communications Server 2007.

Note:
Communicator Web Access and Microsoft Office Live Meeting 2007 cannot be used to join new meetings scheduled on Lync Server 2010. Lync 2010, Microsoft Lync 2010 Attendee, and Microsoft Lync Web App are the recommended alternatives. For details, see Migration Considerations for Meetings (Office Communications Server 2007 Migration).

IM, Presence, Voice, and Video Interoperability

The following table describes the availability of these features during migration.

IM, Presence, and Voice Interoperability with Previous Client Versions

	Lync Server 2010 clients	Office Communications Server 2007 clients
Lync Server 2010 Clients	IM, presence, voice, and video supported	IM, presence, and video supported; some voice feature limitations (see the following section in this topic)

Interaction with Microsoft Office Communicator 2005 clients (basic presence and IM) is supported only if the Office Communicator 2005 user is on a federated network.

Voice Interoperability Considerations

Voice interoperability issues to be aware of are as follows:

Office Communicator 2007 does not support voice features added in Lync 2010, such as call park, team call, response group service, and others.
Call park issues you should be aware of during migration are as follows:
- A call parked by a Lync 2010 user cannot be unparked by clients or devices signed in to an earlier version of Office Communications Server.
- You cannot park a call to a Communications Server 2007 client or device.
- If a PSTN call is routed using the Communications Server 2007 Mediation Server to a Lync user, the Lync user cannot park the call. To park the call, the Communications Server 2007 Mediation Server must be upgraded to Lync 2010.

Conferencing Interoperability Considerations

When a user account is moved from Communications Server 2007 R2 to Lync Server 2010, meetings already scheduled by the user move along with the user account.

Meeting content does not move to the new server. You should advise meeting organizers to reload content into their scheduled meetings after migration.

The following tables describe two conferencing interoperability scenarios:

Previous client version interoperability with Lync Server 2010 meetings
Lync 2010 interoperability with meetings hosted or scheduled on previous server versions

Previous Client Versions and Lync Server 2010 Meetings

Communicator 2007 interoperability	Schedule Lync Server 2010 meetings	Join Lync Server 2010 meetings	Behavior in Lync Server 2010 meetings
Before user is moved to Lync Server 2010	Not supported.	Supported if enabled. For details, see Migration Considerations for Meetings (Office Communications Server 2007 Migration).	No access to new collaboration features unless meeting is escalated to use Lync Web App. No access to new lobby management features.
After user is moved to Lync Server 2010, but before new clients are installed	Continue using the Conferencing Add-in for Microsoft Office Outlook to schedule conference calls and Live Meeting web conferences.	Supported if enabled. For details, see Migration Considerations for Meetings (Office Communications Server 2007 Migration).	No access to new collaboration features unless meeting is escalated to use Lync Server 2010. No access to new lobby management features.

Communicator 2007 interoperability

Schedule Lync Server 2010 meetings

Join Lync Server 2010 meetings

Behavior in Lync Server 2010 meetings

Before user is moved to Lync Server 2010

Not supported.

Supported if enabled. For details, see Migration Considerations for Meetings (Office Communications Server 2007 Migration).

No access to new collaboration features unless meeting is escalated to use Lync Web App.

No access to new lobby management features.

After user is moved to Lync Server 2010, but before new clients are installed

Continue using the Conferencing Add-in for Microsoft Office Outlook to schedule conference calls and Live Meeting web conferences.

Supported if enabled. For details, see Migration Considerations for Meetings (Office Communications Server 2007 Migration).

No access to new collaboration features unless meeting is escalated to use Lync Server 2010.

No access to new lobby management features.

For details, see Migration Considerations for Meetings (Office Communications Server 2007 Migration).

Lync 2010 Interoperability with Communicator Meetings Hosted or Scheduled on Previous Versions of Office Communications Server

Lync 2010 interoperability with Communicator meetings on previous versions of Office Communications Server	Lync 2010 user experience
Scheduling	Lync 2010 users cannot schedule meetings on earlier server versions. When modifying the end date, subject, or attendee list of meetings migrated from previous server versions to Lync Server 2010, users are prompted to convert the meeting to Lync Server 2010.
Joining	No issues.
In meeting	New Lync 2010 features are unavailable.

Lync 2010 interoperability with Communicator meetings on previous versions of Office Communications Server

Lync 2010 user experience

Scheduling

Lync 2010 users cannot schedule meetings on earlier server versions.

When modifying the end date, subject, or attendee list of meetings migrated from previous server versions to Lync Server 2010, users are prompted to convert the meeting to Lync Server 2010.

Joining

No issues.

In meeting

New Lync 2010 features are unavailable.

Interoperability with Existing Custom Applications

For the purposes of this discussion an existing custom application is defined as follows:

The application uses the Microsoft Office Communicator Automation API or the Microsoft Unified Communications Client API.
The application runs in a migration environment, on a machine where Communicator 2007 is connected to a server running Lync Server 2010.

Existing custom applications can sign in to a server running Lync Server 2010 and interact with Lync Server 2010 clients. However, the following limitations apply:

Existing custom applications do not have access to Lync 2010 features.
Running a Unified Communications Client API custom application on the same computer as Lync 2010 is not recommended.
If your organization plans to enable enhanced presence privacy mode, Unified Communications Client API custom applications may need to be rewritten. For details, see What's New in Client Deployment and Lync 2010 New Features in the Getting Started documentation, and the Microsoft Lync 2010 SDK.