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The AUOptions value's Value 2 is Notify for download and notify for install. For an explanation of the available options see https://technet.microsoft.com/en-us/library/cc512630.aspx.

For non-domain computers to use your WSUS server, you may update their registry manually. The minimum settings are:

    # Define registry settings
 $key = 'HKLM:Software\Policies\Microsoft\Windows\WindowsUpdate'
 New-ItemProperty -PropertyType String `
                  -Path $key `
                  -Name WUServer -Value 'http://WSUS1:8530' 
 New-ItemProperty -PropertyType String `
                  -Path $key `
                  -Name WUStatusServer -Value 'http://WSUS1:8530'
 New-ItemProperty -PropertyType DWord `
                  -Path "$key\AU"`
                  -Name UseWUServer -Value 1 
 # Start looking for updates immediately
 Wuauclt /detectnow