Hello,

I am at a customer right now, where we are going to migrate from UM 2010 to UM 2013(Full Exchange migration), while doing a Lync migration as well. My question is simply, is there any way to coexist the two UM environments so that an individual user migration can be done?

Scenario;

UM 2010 and Lync 2010 user gets migrated to Exchange 2013 with his UM as well. This user would be a Exchange UM 2013 user, on a Lync 2010 pool. All my UM dialplans are made pointing to the old pool, which would give routing issues as I see it.

Is there a way to automate Things, so when this user is moved to the new Exchange server, then he will still Work on Lync 2010?

Thank you for helping o

I think here is a god step by step documentation for upgrade the Exchange 2010 UM to 2013

http://technet.microsoft.com/en-us/library/dn169226(v=exchg.150).aspx

Hi Thomas,

You could accomplish the migration?

You should be fine if you follow the link Holger supplied, even if the user is still homed on Lync 2010.  If it doesn't work, you've likely got an issue with your Exchange deployment.  But, it's definitely supported to have Exchange 2013 with Lync 2010: https://technet.microsoft.com/en-us/library/gg412817(v=ocs.14).aspx

You'll also need to move your UM contact objects in Lync to the new pool as well using get-csexumcontact and set-csexumcontact when it's time to migrate this.

Have you tried and it's not functional, or are you just getting ready and want to avoid issues?