<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE xep SYSTEM 'xep.dtd' [
  <!ENTITY % ents SYSTEM 'xep.ent'>
%ents;
]>
<?xml-stylesheet type='text/xsl' href='xep.xsl'?>
<xep>
<header>
  <title>Software Version</title>
  <abstract>This specification provides canonical documentation of an XMPP protocol extension for retrieving information about the software version associated with another XMPP entity.</abstract> &LEGALNOTICE;
  <number>0092</number>
  <status>Draft</status>
  <type>Standards Track</type>
  <sig>Standards</sig>
  <dependencies>
    <spec>XMPP Core</spec>
  </dependencies>
  <supersedes/>
  <supersededby/>
  <shortname>iq-version</shortname>
  <schemaloc>
    <url>http://www.xmpp.org/schemas/iq-version.xsd</url>
  </schemaloc>
  &stpeter;
  <revision>
    <version>1.1</version>
    <date>2007-02-15</date>
    <initials>psa</initials>
    <remark><p>Per a vote of the XMPP Council, changed from Historical and Active to Standards Track and Draft; recommended use of Entity Capabilities instead of Software Version when presence information is available; added proviso to security considerations regarding disclosure of operating system information; added section on Service Discovery.</p></remark>
  </revision>
  <revision>
    <version>1.0</version>
    <date>2003-10-08</date>
    <initials>psa</initials>
    <remark><p>Per a vote of the Jabber Council, changed status to Active.</p></remark>
  </revision>
  <revision>
    <version>0.1</version>
    <date>2003-05-22</date>
    <initials>psa</initials>
    <remark><p>Initial version.</p></remark>
  </revision>
</header>
<section1 topic='Introduction' anchor='intro'>
  <p>The Jabber protocols have long included a method for discovering version information about the software running at another entity's JID. This method makes use of the 'jabber:iq:version' namespace and has been documented variously in Internet-Drafts and elsewhere. Because this protocol is not required by &rfc2779;, the 'jabber:iq:version' namespace was removed from &xmppim;. This specification fills the void for canonical documentation.</p>
  <p><em>Note Well: The jabber:iq:version protocol SHOULD NOT be used to determine the identity of entities from which an application receives presence (e.g., contacts in a user's roster and certain kinds of gateways); &xep0115; SHOULD be used instead. However, the jabber:iq:version protocol MAY be used to determine the identity of entities from which an application does not receive presence (e.g., servers and many kinds of components). The jabber:iq:version protocol MAY also be used to determine information available only via jabber:iq:version (e.g., operating system information) for contacts from which a user receives presence, but only if the user specifically requests such information for a particular contact.</em></p>
</section1>
<section1 topic='Protocol' anchor='protocol'>
  <p>The 'jabber:iq:version' namespace provides a standard way for Jabber entities to exchange information about the software version used by the entities. The information is communicated in a request/response pair using an &lt;iq/&gt; element that contains a &lt;query/&gt; scoped by the 'jabber:iq:version' namespace. The following children of the &lt;query/&gt; are allowed in an IQ result:</p>
  <ul>
    <li>&lt;name/&gt; -- The natural-language name of the software. This element is REQUIRED in a result.</li>
    <li>&lt;version/&gt; -- The specific version of the software. This element is REQUIRED in a result.</li>
    <li>&lt;os/&gt; -- The operating system of the queried entity. This element is OPTIONAL in a result (see also the <link url='#security'>Security Considerations</link>).</li>
  </ul>
</section1>
<section1 topic='Examples' anchor='examples'>
  <example caption='Querying Another Entity for its Software Version'><![CDATA[
<iq
    type='get'
    from='romeo@montague.net/orchard'
    to='juliet@capulet.com/balcony'
    id='version_1'>
  <query xmlns='jabber:iq:version'/>
</iq>
  ]]></example>
  <example caption='Receiving a Reply Regarding Software Version'><![CDATA[
<iq
    type='result'
    to='romeo@montague.net/orchard'
    from='juliet@capulet.com/balcony'
    id='version_1'>
  <query xmlns='jabber:iq:version'>
    <name>Exodus</name>
    <version>0.7.0.4</version>
    <os>Windows-XP 5.01.2600</os>
  </query>
</iq>
  ]]></example>
  <p>The standard error conditions described in &xep0086; apply (e.g., service unavailable if the entity does not support the namespace).</p>
</section1>
<section1 topic='Determining Support' anchor='disco'>
  <p>In order for a requesting entity to determine if a responding entity supports result set management, it SHOULD send a &xep0030; information request to the responding entity:</p>
  <example caption='Requesting entity queries responding entity regarding protocol support'><![CDATA[
<iq from='stpeter@jabber.org/roundabout'
    to='conference.jabber.org'
    id='disco1'>
  <query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>
  ]]></example>
  <example caption='Responding entity communicates protocol support'><![CDATA[
<iq from='conference.jabber.org'
    to='stpeter@jabber.org/roundabout'
    id='disco1'>
  <query xmlns='http://jabber.org/protocol/disco#info'>
    ...
    <feature var='jabber:iq:version'/>
    ...
  </query>
</iq>
  ]]></example>
</section1>
<section1 topic='Security Considerations' anchor='security'>
  <p>Revealing the application's underlying operating system may open the user or system to attacks directed against that operating system; therefore, an application MUST provide a way for a human user or administrator to disable sharing of information about the operating system.</p>
</section1>
<section1 topic='IANA Considerations' anchor='iana'>
  <p>This document requires no interaction with &IANA;.</p>
</section1>
<section1 topic='XMPP Registrar Considerations' anchor='registrar'>
  <p>The 'jabber:iq:version' namespace is registered in the protocol namespaces registry maintained by the &REGISTRAR;.</p>
</section1>
<section1 topic='XML Schema' anchor='schema'>
  <code><![CDATA[
<?xml version='1.0' encoding='UTF-8'?>

<xs:schema
    xmlns:xs='http://www.w3.org/2001/XMLSchema'
    targetNamespace='jabber:iq:version'
    xmlns='jabber:iq:version'
    elementFormDefault='qualified'>

  <xs:annotation>
    <xs:documentation>
      The protocol documented by this schema is defined in
      XEP-0092: http://www.xmpp.org/extensions/xep-0092.html
    </xs:documentation>
  </xs:annotation>

  <xs:element name='query'>
    <xs:complexType>
      <xs:sequence minOccurs='0'>
        <xs:element name='name' type='xs:string' minOccurs='1'/>
        <xs:element name='version' type='xs:string' minOccurs='1'/>
        <xs:element name='os' type='xs:string' minOccurs='0'/>
      </xs:sequence>
    </xs:complexType>
  </xs:element>

</xs:schema>
  ]]></code>
</section1>
</xep>