SCP when installing Exchange 2019 into 2013 environment

Hi all,

We will be installing 2019 into an existing 2013 environment.

I just have a question regarding the Server Connection Point (SCP).  We will be installing then changing the 2019 servers SCP to point to where our 2013's point (mail.ourdomain.com).

There will be a period during the 2019 install where its SCP points to itself before we can change it.  How does this affect clients?

• Does it only affect those opening Outlook 365 for the first time (setting up a new profile)?
• Could it affect clients who have Outlook actively open?
• Could it affect clients who already have a profile created but open Outlook?

We would be doing the install out of hours but was just curious how Outlook 365 uses the SCP?  There will be 4 Exchange servers registered (2 x 2013 and then 2 x 2019).  When a client connects does it randomly choose one of the servers or does it preference the 2019 servers?

thanks

justin