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The local edition consists of all components and reference set members that belong to the focus module and the two modules on which the focus module depends - 

Concept
ShowParts term t 900000000000207008 |SNOMED CT core module|

and the

Concept
ShowParts term t 900000000000012004 |SNOMED CT model component module|

. As discussed previously, the version specific dependencies must be stated in the  Module Dependency Reference Set.

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Versioned Edition

There are many use cases that require a date specific version of an edition, including specifying the substrate of a SNOMED CT query, and specifying the version of SNOMED CT used to code a specific data element in a health record. A

Gloss
t versioned edition

includes  includes the contents of the specified version of the focus module, plus the contents of all

Gloss
t versioned modules

on  on which the versioned focus module depends (as specified in the

Concept
ShowParts term t 900000000000534007 |Module dependency reference set|

). The version of an edition is based on the date on which the edition was released. Many extension providers release their extensions as a versioned edition, using regular and predictable release cycles. For example, the International Edition is released by SNOMED International twice a year, on 31st January and 31st July.

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If a situation arises in which an extension has two equally dependent modules, then a new focus module may need to be created, with dependencies defined to all other modules in the edition. In this case, the focus module may contain only the components and reference set members used to define the module concept itself and its dependencies as defined in the module dependency reference set. 

Caption reference
CapRefId most-dependent-module CapRefType Figure

 below illustrates a situation in which two (equally dependent) sibling modules exist - national module A and national module B - which are both dependent  on the 

Concept
ShowParts term t 900000000000207008 |SNOMED CT core module|

 and the

Concept
ShowParts term t 900000000000012004 |SNOMED CT model component module|

, and are not dependent on each other. To form a national edition, which contains both national module A and national module B, a new focus module must be created t hat is dependent on all other modules in the edition. The concept id of the new focus module is then used in the URI of the national edition that contains both national module A and national module B.

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