Yamaha has confirmed to TheWhippinpost that yes, it's definitely true, it has (long) discontinued support for its erstwhile popular MIDI XG softsynths: the Yamaha SYXG-50, and Yamaha SYXG100.

In a written reply to TheWhippinpost, it said:

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

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