In April 2005, Apple updated DVD Studio Pro to support authoring HD content. DVD Studio Pro 4 allowed for the burning of HD DVD content to both standard DVDs and HD DVD media (even though no HD DVD burners were available for Macintosh). For playing back HD DVD content burned to a standard DVD, Apple requires a PowerPC G5, Apple DVD Player v4.6, and Mac OS X v10.4 or later. Version 4 was the first version to drop support for Mac OS 9.