Original used linear interpolation, causing aliasing at high playback rates. Solution: Rebuild uses cubic Hermite interpolation with optional anti-aliasing oversampling.
It looks like you’re referencing a specific software project or plugin update — likely related to and a rebuild of its sound engine (“SynsoEmu”) from a version labeled “17”. Steinberg - Hypersonic 2.0 -Rebuild SynsoEmu- - 17