/Library/LaunchAgents folder, where I found a file named com.micromat.SMSDaemon.plist.
I moved the .plist file to the Trash, logged out, logged back in and deleted the file. Finally, this put a stop to all Syphone-related messages in Console.
In the end, I cannot say for sure that these error messages caused any problems beyond the annoyance of their repeated appearance. Still, I was happy to be done with them.
More generally, if you are plagued by this or any other repeating message in Console, you should now have a better idea what to do about it. And, if you're a developer, I have a request: Design your software so that they don't generate these sort of messages in the first place, especially not when the user isn't even using your program anymore.
Read article at Macworld.com