Scripting Open error: "Opening session using command-line parameter in scripting is deprecated."

I am trying to do a simple file transfer to an SFTP site using a .bat file to call WinSCP.com, passing it a basic script file. This is how all the examples I can find on the internet seem to show how to do things. If I manually type the open/put statements into the CMD window, everything works great, but when I try to run the .bat file, I get the error:
"Opening session using command-line parameter in scripting is deprecated. Use 'open' command instead".

The .bat file simply contains:
Winscp.com /script = SFTPTest.txt

The SFTPTest.txt file contains:
# Connect to SFTP site
open sftp://login:password@hostsite
# Upload the file to current working directory
put Testfile.TXT
# Disconnect
close
# Exit WinSCP
exit

Any ideas how to get this working? My hope is to be able to schedule the .bat file to run daily to copy the file to the SFTP site.

Thanks

I reposted this in the "Scripting & Automation" forum - please disregard this one

https://winscp.net/forum/viewtopic.php?t=23092