The HSD-64 is the next generation digital instrument for the mixed-signal ETS-800. This paper, published prior to the instrument release (target fall of 2024), aims to provide a preview. With doubled channel density, the HSD-64 enables higher site count and lower cost of test. Many feature enhancements are offered over the legacy HSD-32; including deeper memory, DSSC use model improvements, DIB Access, and others. These features benefit a variety of industry segments like Mobile Power, Automotive SoCs, Motor Controllers, and Power Management Devices. Compatibility has been a major topic in recent product releases; MST-2024A and the HSD-64 are no different. Considerable hardware and software efforts have gone into an emulation mode. Emulation mode significantly reduces the user effort when converting existing apps from HSD-32 to HSD-64. This paper will provide an overview of the features. It will also discuss the updated use models for DIB Access, DSSC, and Emulation Mode.