Recommendation ITU-T X.1528.4 defines the specification for common platform enumeration (CPE) applicability language. The CPE applicability language specification is part of a stack of CPE specifications that support a variety of use cases relating to IT product description and naming. The CPE applicability language data model builds on top of other CPE specifications to provide the functionality required to allow CPE users to construct complex groupings of CPE names to describe IT platforms. These groupings are referred to as applicability statements because they are used to designate the platforms to which particular guidance, policies, etc. apply. This Recommendation defines the semantics of the CPE applicability language data model and the requirements that IT products and CPE applicability language documents must meet to claim compliance with this Recommendation.

This is achieved by listing the relevant clauses of the NIST Interagency Report 7698: Common Platform Enumeration Applicability Language Specification version 2.3 and showing whether they are normative or informative.