Variants

Variant - Definition and characteristics

A 'variant' is a restricted version of a global message definition.

For example, a variant may exclude the portions of the global message definition that are rarely used in order to provide a message definition that is easier to implement and still covers 80% of the cases. 

Variants may facilitate adoption of ISO 20022 message definitions by removing complexity and/or making it much clearer how to use a message definition in a specific context.

Another example is an STP variant of a global message definition which excludes all the options that would require manual processing of the message instance and thus ensures straight through processing (STP) of the messages. Such a variant can be more attractive than the global message definition and help adoption of ISO 20022.

The advantages of a variant include:

  • a specific dedicated documentation (Message Definition Report) that is easier to understand since it eliminates all the portions from the global message definition that are not used
  • a sharper schema that can be used to generate or validate instances of the variant. Thanks to these schemas, users do not have to implement sets of conditional rules to obtain similar restricted message instances from the global message format. The global message definition, however, may be used to build applications that can process all message instances generated either through the global message schema or through the schema of any of its variants.

To facilitate the use of variants, the message identifier of ISO 20022 message definitions includes a 3-digit 'variant number', which is set to "001" to identify the global message definition and offers the possibility to identify up to 998 message variants. This explicit identification of variants allows the easier routing, validation and processing of the instances using, for example, the variant schemas.  

Development and maintenance of variants

A variant is a specific ISO 20022 message definition that requires the development of a specific ISO 20022 message model that eliminates all the unnecessary elements of the global message definition and replaces the components that are restricted by new derived components. Specific modelling guidelines must be used to create sharper message concepts derived from and still associated with the original message concepts of the global message definition.  Therefore, the development of a variant requires the same kind of expertise as the development of a new message definition.

It also requires some commitment of the submitting organisation for their maintenance. A message variant is attached to a specific version of the global message definition. However, the variant has its own maintenance lifecycle which is independent from the maintenance lifecycle of the global message definition, that is, new versions of the variant may be associated to the same version of the global message definition, provided they are still restrictions of this version of the global message definition.

As a consequence, the version number of the variant is independent of the version number of the global message.

Example:

Global message definition abcd.001.001.01 has a variant abcd.001.002.01

A new version of the variant is registered that includes an additional restriction on the global message definition.

Hence, message definition abcd.001.001.01 is now shown in the Catalogue of Messages with variant abcd.001.002.02, while the first version of the variant is moved to the Message Archive. 

If the global message definition is maintained, its variants may need to be maintained as well to remain associated with the new version of the global message definition. If the changes to the global message definition do not affect a variant, then the variant does not need to change and keeps the same version number, while the version of the global message definition changes.

Example:

Global message definition abcd.001.001.01 has a variant abcd.001.002.02. The global message definition is modified to remove a series of elements and a new version abcd.001.001.02 is registered

  • If the variant abcd.001.002.02 does not use these elements, then the same version abcd.001.002.02 can remain associated with the new version of the global message definition in the Catalogue of Messages.
  • if the variant abcd.001.002.02 uses some of these removed elements, then a new version of the variant abcd.001.002.03 is to be developed to be associated to the new version of the global message definition. Version 02 of the variant will be moved to the Message Archive with version 01 of the global message definition.

Note: if a community using a variant wants to update the variant in a way that is no longer compliant with the global message definition (for example, add elements that are not present in the global message definition), then this community must first submit a change request (CR) to the RA to request that the global message definition be updated accordingly.  It is the responsibility of the SEG in charge of the global message definition to decide whether it makes sense to update the global message definition as requested. Alternatively, the SEG may propose that the SupplementaryData component be used by the variant community to accommodate their additional needs.

Variants and Implementation Guidelines

ISO 20022 message variants are expected to support the adoption of ISO 20022 messages globally, that is, either internationally by a specific segment of the industry or by a significant portion of the community. Variants are not supposed to replace Implementation Guides or Usage Guidelines that describe the specific way of using a message in a particular context or by a specific community of users. Implementation Guidelines used by initiatives adopting ISO 20022 messages are not registered and published by ISO 20022 but can be identified (with the place where to find them) as part of the ISO 20022 Adoption Initiatives Report. Implementation Guidelines can be maintained by the owners whenever required without requiring any expertise in ISO 20022 message development. 

Registration process for variants

In general, requests for registration of variants relate to several or all message definitions of a particular ISO 20022 message set. Therefore, each request for registration of variants, even if for a single message definition, is associated to a particular ISO 20022 message set and the resulting set of variant(s) is published together with the message set it relates to in the specific Business Domain Catalogue of Messages (Payments, Securities, Trade Services, Cards, FX).

1.    Registration of new variants (flow chart of the process)

The registration of a (set of) message variant(s) requires submission and approval of a specific Business Justification for Variant.

As for global message definitions, the Business Justification goes first through a ‘commenting period', during which it is reviewed by the RMG and the SEG that approved the global message set, and is then submitted to the approval of the RMG. The process is similar to the registration process for new global message definitions except that there is no need for a SEG review/approval of the variant message definitions, once developed by the submitting organisation. Indeed, as the SEG already approved the global message definitions, all variants of these message definitions are de facto also approved. When the RA receives the variant message model developed by the submitting organisation, the RA verifies that the candidate variants are true variants (that is, actual restrictions) of the related global message definitions. After verification of the compliance with ISO 20022 specifications and the compliance with the global message definitions, the RA registers and publishes the variants. The published documentation includes a description of the variants provided by the submitting organisation, a Message Definition Report (Part 2 only, since Part 1 and Part 3 of the global message set applies to the variants as well) and XML or ASN.1 schemas.

The registration of variants thus includes the following steps: 

  1. the submitting organisation submits a specific Business Justification to the RA that is distributed to the RMG and the SEG(s) that approved the global message set for comments (1month)
  2. the submitting organisation addresses the received comments and submits an updated Business Justification with disposition of comments to the RA (3 weeks)
  3. the updated Business Justification is submitted to the approval of the RMG (1 month). During this 1-month period, the RA organises a conference call to give the opportunity to RMG members to ask questions to the submitting organisation before casting their vote
  4. if the Business Justification is approved, the RA allocates a variant number to the future set of variants and communicates it to the submitting organisation
  5. the submitting organisation develops the candidate variant message model and submits it to the RA
  6. the RA verifies the ISO 20022 compliance of the model and the compliance of the variants with the related global message definitions (= true variants)
  7. the RA registers and publishes the set of variants together with the related global message set in the respective business domain catalogue: Payments, Securities, Trade Services, Cards, FX.

2.    Maintenance of existing variants

As said above, the maintenance lifecycle of variants is independent of the maintenance lifecycle of the related global message definitions. This means that the maintenance of the variants may use a different timing - and a different frequency - from the ISO 20022 maintenance process.

Submitting organisations responsible for variants may develop new versions of their variants and submit them to the RA for registration whenever relevant, provided these new versions are still true variants of the related versions of the global message definitions. Requests for change to a variant are to be addressed directly to the submitting organisation in charge of the variants. Such change requests do not need to be addressed to the RA and do not need to be approved by the SEG since, by definition, any new version of a variant must still be compliant with the related version of the global message definition which has already been approved by the SEG.  However, in case of a dispute between a submitter of a change request and the submitting organisation, the SEG in charge of the global message set may be asked to arbitrate.

The maintenance of variants includes the following steps:

  1. the submitting organisation informs the RA about the development of a new version of the variants and the expected timing of submission to the RA
  2. the submitting organisation develops the candidate model of the new version of the variants and submits it to the RA with a description of the updates vis-à-vis the previous version of the variants
  3. the RA verifies the ISO 20022 compliance of the model and the compliance of the variants with the related global message definitions (= true variants)
  4. the RA registers and publishes the new set of variants together with the description of the updates in the respective business domain catalogue: Payments, Securities, Trade Services, Cards, FX.

If a new version of a global message definition is published as a result of the ISO 20022 maintenance cycle, the RA moves the previous version of the global message definition and all related variant message definitions to the Message Archive and informs the submitting organisations responsible for these variants. It is up to each submitting organisation to check whether their variants are still compliant with the new version of the global message definitions and,

  • if yes, to re-submit the variants to the RA for registration and publication with the new version of the global message definitions
  • if not, to develop a new version of the variants and submit them to the RA for registration and publication with the new version of the global message definitions.

To make sure that the submitting organisations responsible for variants are aware of the potential changes to the global message definition, whenever change requests (CR) are received for a global message definition which has variants, the SEG(s) in charge invites the submitting organisation(s) responsible for the global message definition and the submitting organisation(s) responsible for its variants to participate in the evaluation of these change requests (see maintenance process of global message definitions).