Lync 2013 conferences when using Outlook/Join Launcher with Lync 2010 Coexistence

During the coexistence period between Lync 2010 and Lync 2013 an error occurs when a Lync user tries to join a Lync 2013 hosted conference.

Also on the Lync 2013 Server a Lync Event error LS User Services 30988 is logged.

This is resolved by editing the Web.config files in Lync 2010 and Lync 2013 adding the following key:

1. <add key="disableConferenceKeyVerification" value="true" />

2.  <add key="disableRedirectionToHomePool" value="false" />

that key needs to be added to the following files on the Lync 2010/2013 Front-End Servers:

C:\Program Files\Microsoft Lync Server 2010\Web Components\Join Launcher\Int\web.config
C:\Program Files\Microsoft Lync Server 2010\Web Components\Join Launcher\Ext\web.config

After applying the change and perform IISRESET, the Lync 2010 and 2013 servers.