Service Interface for Real Time Information
CEN/TS 15531

Siri Versions

Siri uses a systematic versioning scheme in line with GovTalk & e-Gif  standards.

  1. Version Numbering
  2. Version Location
  3. Version Identifiers

1. Version Numbering

All Siri schemas have a version Identifier of the form N.Ma, where:

  • N indicates a Major release, e.g. "2.0". A major release is not necessarily strictly backwards compatible with the previous release.
  • M indicates a Minor release, e.g. "2.1". A minor release is backwards compatible with the previous release, providing any new optional features added in the release are not used
  • a indicates an Unapproved draft, e.g. "1.0a", "4.3a". A letter suffix indicates that the release is not yet officially approved or released.

2. Version Location

2.1 Schema versions

Siri schema versions are always located at a specific, versioned URL. The URL has the general form:



Version 1.0 of SIRI:

Draft of Version 2.0 of SIRI:

2.2 Namespace versions

Note that the namespace used for SIRI is not itself versioned, thus:

<xs:schema targetNamespace=""

2.3 Directory Structure

SIRI schema artefacts are organised into a hierarchical directory structure  relative to the root domain. Within this hierarchy a standard structure is used to organize the base trident schemas and the dependent schemas.  Note that the other schemas are in sibling directories not child directories of the Siri schema.

For example the directory structure could be as follows:











3.  Version Identifiers

3.1 Schema Version Identifiers

All Siri schema versions have a formal version identifier in the header element, for example :

<xs:schema targetNamespace=""








3.2 Document Version Identifiers