We are going to upgrade from 10.1.600 to 10.2.300 in a few weeks. We are installing the client to test that is pointed to our test server. What’s the best way to repoint those clients to the live server once we go live? I’m a bit confused about how the local client determines which server to grab configs from.
What the Public Cloud Users do is have your Epicor folder and within that folder, have a client for Live and a Client for Test/Pilot. (One for Embedded Education if you have it). You can then install the Live Client now pointing to the Live Server and when you’re ready, they would just use the Live Short Cuts.
And we keep this going for testing patches as well. Upgrade your Test/Pilot - do your testing then upgrade the Live.
In the sysconfig file is a DeploymentServer node that tells the client where to get upgrades from. Frankly, just installing the Live ahead of time pointing to the live server is probably the cleanest way to go. If needed, disable users ahead of time when you spin up live until you’re ready then re-enable once up. You can do this with DMT if you have it.
Mark W.
@Mark_Wonsil has a good plan for sure.
We use different config files for each environment. Coming from 10.1 to 10.2 this is ok cause the client is in a totally different folder. However when installing patches at the version level the way @Mark_Wonsil said to go is better. You can just update the shortcut everyone is using to a new one pointed at the sysconfig for the live application server when you are ready. Ensure they are at the same patch level test and live or the client will reset.
Just be clear, @Mark_Wonsil is following the Cloud Team’s plan. 
They create the short cuts for the target folders under the Epicor\ERPDT folder (Live, Pilot, Education, …) and each is upgraded separately.
When we were testing Azure AD, they added another folder under the Epicor folder. Works like a champ for running multiple client versions at the same time.