Bryan,
I understand your concern but please, do not worry. It's been my experience and my customers that whatever was changed in the latest release, it is not significant and only minor implementations for things I don't even know what they corrected. If, in any time during the next 2 years, anything new which really would make a difference comes out in a newer release, like maybe 2.0, you can get yours upgraded at no charge to you from any service center that works on Yamaha keyboards. I stress..............don't worry about the operating system, just enjoy your psr2000.
George Kaye
Kaye's Music Scene
Reseda, California