Exchange 2007 migration to Exchange 2013

Hello Exchange experts,

I’m Planning an Exchange migration (EX07 to EX13) and despite to have read many many tutorials and technet opinions, I cannot see the correct path to migrate. I hope someone can help me.

- Actual Infrastructure:

     1 Physical server (SERVER_08): DC + Exchange 2007. IP: 192.168.1.10

- Future Infrastructure:

     1 Physical Server (SERVER_2012R2): DC, GC, FS. IP: 192.168.1.50

     1 Physical Server (EX2013): CAS,Mailbox. IP: 192.168.1.51

My questions come once I’ve prepared the squema and I have to start with the Exchange Migration. As far as I know, I think the steps and infrastructure behavior will flow in this way:

• Initial State: Only one Exchange2007 installed and all the clients point to this server, and thus in this moment the value of SCP is the initial Exchange Server SERVER_08.In SERVER_08 there is one self-certificate with this names: SERVER_08.test.local and SERVER_08 and all the Outlook clients and Windows Phones use this certificate. This works perfectly.

•  I install a secondary Exchange (EX2013) in a new server but in the same internal domain (test.local).Once the second Exchange server is installed, the SCP is automactly updated with the new SCP pointing to this Exchange 2013 (EX2013).

      So that the clients don’t give them  a prompt message, the SCP must be changed with PowerShell to point the initial    Exchange Server (SERVER_08). (Right?)

•  Create a A register (mail.test.local) pointing to the new Exchange 2013 (EX2013 - 192.168.1.51).

        At this point, I understand that the clients can coexist with both Exchange Servers (EX07/EX13) and no one will be prompted with new certificate issues. Right?

• Once the Mailbox Databases/Connectors are migrated to the new exchange 2013, I need to modify again through PowerShell the SCP value with the new EX2013 (mail.test.local).

• When the clients open again the Outlook client, will be prompted to agree the new Exchange 2013 certificate andeverything will work fine during the next 5 years (Exchange 2013 self-certificate lifetime).

I’ve been reading many tutorials and I want to make sure the steps until coexist both Exchange works fine, and obviously  if the experts can suggest me something.

Thanks in advance

Best Regards

Tecnico Superior de Sistemas