Yamaha has confirmed to TheWhippinpost that yes, it's definitely true; they have (long) discontinued support for both their erstwhile popular MIDI XG softsynth's: The Yamaha SYXG-50 and Yamaha SYXG100

In a written reply to TheWhippinpost's enquiry, they said the following:

We are sorry to inform you that Softsynthesizer has been discontinued. We will help our customers as much as we can, but we can't guarantee that we can provide the desired help for certain questions, since there is no additional updates for this program.
Sorry for any inconvenience.

I know from the visitor logs and emails I still occassionally receive that this was worth chasing-up. Indeed, my own searches on Google failed to return any official announcement when I myself looked into it, so I just hope that this means you can now go about your daily business once again and give up the chase... Go on, spend this precious time TheWhippinpost has given back to you by grabbing your missus/boyfriend around the waist, and dancing the Fandango around your gatepost naked.

Oh... and don't forget to send in your pictures so we can all share in your joy, thanking you.