The Amd.1 specifies an additional interchange format and slight modification to ISO/IEC 9541-2.
The specification is applied only when additional font properties defined by Amd.2 and/or Amd.3 to ISO/IEC 9541-1 are employed. The properties are optional and make it possible to address advances in font technology in addition to those defined in ISO/IEC 9541-1.
The additional interchange format is described by SGML (Standard Generalized Markup Language) conforming to ISO 8879:1986 and its Technical Corrigendum 2 (Annex K: Web SGML Adaptations).
The Amd.1 was published in Dec. 2000.