FIXED – stsadm upgrade command has been replaced by psconfig.exe
Recently I came across the error below when upgrading a SharePoint 2016 farm. Expected product behavior and simply a case of training SharePoint Administrators to use PSCONFIG.EXE command line instead. Cheers! 
Error Screenshot
stsadm -o upgrade -inplace b2b –force Command line error. Invalid parameter. stsadm –o upgrade command has been replaced by psconfig.exe -cmd upgrade
New Command
PSCONFIG -cmd upgrade -inplace b2b -wait -cmd applicationcontent -install -cmd installfeatures -cmd secureresources -cmd services -install
