two years ago 12.0 was badly misbehaving on Solaris 2.5. It turned out Sybase was relying on the Solaris Thread Library for the first time. Under heavy load, the Solaris code failed to restore processor registers after thread-switching. Total mayhem. At that time, there was even a warning on the top page of support.sybase.com, essentially saying 12.0 wasn't quite working on Solaris 2.5 or 2.6.
Now a project intends to upgrade to 18.104.22.168 under Solaris 8. Has the old threading bug been resolved ? Any more issues with these versions ?