I need to upgrade my existing MS Azure AD Connector Server

[Marian17]

I am running a Windows 2012 R2 OS Server

Azure AD Connect version 1.4.38.0

Running SQL Server 2012 version 11.0.6251

I know all of this need to be upgraded

But I also do not what any impact on any users, we have approx 90K users

Is this just a matter of creating a new Windows 2019 Server, installing the latest version of SQL Server and Azure Connect

If I keep the server names the same would that help?

If I removed Azure AD connect on the existing server so I can install it on the new 2019 Server, how does this impact users?

Thanks

[#2]

The best approach would be to perform swing migration by installing AAD connect in new server and decommission the old AAD connect once the new server is up and syncing with no issues.

Once the old AAD connect servers are removed from the network you can rename the new AAD connect server to the old names and IPs.

Here is the link for detailed explanation of swing migration: https://docs.microsoft.com/en-us/azure/active-directory/hybrid/how-to-upgrade-previous-version