Splashtop SOS for Mac OS X 10.6.8?

I'd like to help a friend with a "antique" MacBook Pro that's limited to Mac OS X 10.6.8.

I've been unsuccessful Googling for a release of Splashtop SOS that runs on 10.6.8. The earliest release I have in my personal archive is Splashtop SOS 3.1.8.0.  When I mount that disk image, there's a "no entry" symbol over the SOS app.

Is there a Splashtop SOS release that runs on Mac OS X 10.6.8?

-- Ward