A change was recently made to the Login-AzureRmAccount PowerShell cmdlet which may break existing scripts.
For older versions of Azure PowerShell you would use the following to log into Azure US Government:
Login-AzureRmAccount –EnvironmentName AzureUSGovernment
With the new version of Azure PowerShell you will instead use:
Login-AzureRmAccount –Environment AzureUSGovernment
It is a simple change but you need to be aware of it in case you upgrade your Azure PowerShell and notice your scripts are no longer working.