Original: The Reinheitsgebot is no longer part of German law: it has been replaced by the Provisional German Beer Law (Vorläufiges Deutsches Biergesetz (Provisional German Beer-law of 1993)), which allows constituent components prohibited in the Reinheitsgebot, such as wheat malt and cane sugar, but which no longer allows unmalted barley.
Simplified: It has been replaced by the Provisional German Beer Law Vorläufiges deutsches Biergesetz Provisional German Beer Law, which allows things prohibited in the Reinheitsgebot, such as wheat malt and cane sugar, but which no longer allows unmalted barley.