This is an update to my my previous post on migration http://blogs.technet.com/jenstr/archive/2007/11/27/migrating-from-lcs-2005-sp1-to-ocs-2007-which-client-can-you-use-when.aspx. I’ve only updated the table. For the full details please refer to the previous post.

Row Client connects with User homed on Enabled for Enhanced Presence Enhanced Presence Mode set Connection works?
1 OC 2005 LCS 2005 SP1 N/A N/A Yes
2 OC 2007
OC 2007 R2		 LCS 2005 SP1 N/A N/A No
3 OC 2005 OCS 2007
OCS 2007 R2		 No No Yes
4 OC 2007 OCS 2007
OCS 2007 R2		 No No No
5 OC 2005 OCS 2007
OCS 2007 R2		 Yes No Yes
6 OC 2007 OCS 2007
OCS 2007 R2		 Yes Yes (sets it on first successful connection) Yes
7 OC 2005 OCS 2007
OCS 2007 R2		 Yes Yes No
8 OC 2007 R2 OCS 2007 Yes Yes No

Some key points to note:

  • OC 2007 R2 can only connect to OCS 2007 R2
  • Users homed on OCS 2007 R2 can chose between OC 2007 and OC 2007 R2