ISO 20022 Handbook

1. Introduction

This ISO 20022 handbook contains all necessary information on the Bank’s migration of CHAPS and RTGS to ISO 20022 messaging. It provides comprehensive information on our approach, policies and timelines, as well as signposting key technical resources, such as the location of technical documents and detail about industry readiness and testing. This document replaces previous publications such as the CHAPS and RTGS ISO 20022 migration publication that was issued in October 2020 and updated in September 2021.

This information is aimed at CHAPS Direct Participants, RTGS account holders, CHAPS indirect participants and technology partners. It also includes information relevant for payment users who make, receive or process CHAPS payments, or other stakeholders with an interest in the future of UK payments. CHAPS Direct Participants in particular should ensure full understanding of information in this ISO 20022 handbook, while Section 4 - non-payment message migration, is also relevant for RTGS account holders.

2. CHAPS migration timetable and approach

The below timetable contains key milestones that will impact CHAPS participants and RTGS account holders.

19 June 2023 – Enhanced ISO 20022 messaging in CHAPS

We migrated the live CHAPS service to ISO 20022 messaging on 19 June 2023. At this point:

• CHAPS moved to the SWIFT InterACT service. All CHAPS Direct Participants will need to be able to receive enhanced ISO 20022 payment messages using only the enhanced XML message schemas. The data sent in CHAPS payments must now contain at minimum the requirements and rules for the existing MT message formats, and sending enhanced data will be optional. However, we continue to encourage Direct Participants to send enhanced data (ie above that required or supported in existing MT message formats) where possible, taking into account relevant international guidance. For more detail, please see our Policy Statement: Mandating ISO 20022 Enhanced data in CHAPS.
• CHAPS Direct Participants are able to choose whether to send/receive non-payment messages (e.g. statements, notifications and liquidity-related messages) in either the existing MT or the new ISO 20022 format until the new RTGS code ledger and settlement engine goes live in Spring 2025.

New RTGS core ledger and settlement engine

The new RTGS core ledger and settlement engine will go live in Spring 2025, at which time:

• CHAPS Direct Participants must continue to be able to receive enhanced messages, and are encouraged to send enhanced data in their messages where possible, but this is optional.
• All CHAPS Direct Participants will need to send and receive non-payment messages (for example, statements, notifications and liquidity-related messages) in the relevant ISO 20022 format.

Mandating enhanced data

• We will mandate certain elements of enhanced data, from May 2025, maintaining the window between implementation and mandating. In particular, it will mandate the use of Purpose Codes and LEIs for payments between financial institutions (all pacs.009 CORE messages and certain pacs.008 messages). We will also mandate Purpose Codes for property transactions. For more detail, please see our Policy Statement: Mandating ISO 20022 Enhanced data in CHAPS.
• From November 2025, we will mandate that where remittance data is included in pacs.008 payment messages, it must be structured. CHAPS Direct Participants will also be able to start sending Hybrid Addresses, but are encouraged to send fully Structured Addresses.
• From November 2026, the use of fully unstructured Addresses in any CHAPS payments will be rejected, in line with international standards.
• We will consider further enhancements to ISO 20022 message schemas and the CHAPS rulebook to mandate or incentivise full use of the ISO 20022 messages (please see our Policy Statement: Mandating ISO 20022 Enhanced data in CHAPS).

3. ISO 20022 message schemas and how to access them

MyStandards

We have published on MyStandards the enhanced ISO 20022 message schemas for CHAPS, payment system operators, and other RTGS account holders, together with further Technical Guidance. 

The current enhanced message schemas are up-to-date and align with the latest international market practice. These are the message schemas that CHAPS Direct Participants, payment system operators, and other RTGS account holders should implement and develop against, in line with the ISO 20022 approach and timelines as set out in this section and Section 1.

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Return messages

On 19 June 2023, we also introduced the pacs.004 return message, which does not have an MT equivalent. This replaces the practice of returning CHAPS payments via MT 202 messages. Further detail is provided in the Technical Guidance found on MyStandards.

Migration of collateral-related messages 

Interim procedures on operation of the Euro Liquidity Bridge facility can be found in the RTGS Reference Manual. These procedures will be operated manually until the introduction of the new core ledger and settlement engine for RTGS. CHAPS Direct Participants will need to contact the Bank prior to funding the Bank’s Euro cash collateral account at DNB using their institution’s standard communication with the Bank for RTGS.

Any securities messages to manage other collateral movements (via the Bank’s collateral management systems, which are separate to RTGS) will remain in the FIN MT format for the foreseeable future. The Bank’s long-term intention is that these will move to ISO 20022 messages, however we are prioritising the migration of payment messages prior to November 2025. 

List of messages used in CHAPS

4. Non-payment message migration

Non-payment messages are also migrating to the new ISO 20022 format. These include the existing statement, notification and report messages, MT 298/nnn and MT 950 messages.

If your organisation currently receives a daily statement directly from RTGS, you will need to update your internal systems to be able to accept the new camt.053 message once the new RTGS core ledger and settlement engine is implemented.

If you will not be ready to receive the camt.053 messages by Spring 2025, you may be able to build or buy a translator service to convert the camt.053 message into MT 950 messages for use in your internal systems.

If you have any queries, please contact RTGSReadiness@bankofengland.co.uk. More information can be found in the historic publication: Migration approach of non-payment messages to the ISO 20022 messaging standard. This is a static document so please check the RTGS extranet for more detailed information and dates.

5. Enhanced data policy and guidance

The Policy Statement: Mandating ISO 20022 Enhanced Data in CHAPS sets out the Bank’s policy position for the implementation of enhanced data in CHAPS through the ISO 20022 messaging standard. It also consults on how we intend certain policies around enhanced data to expand from 2027.

The Bank supports enhanced data and strongly encourages each Direct Participant to use enhanced data once they are capable of sending. From May 2025, we will mandate the use of Purpose Codes and LEIs for CHAPS payments between financial institutions, and mandate the use of Purpose Codes for property transactions. For further information on Purpose Codes please see the UK recommended Purpose Code list and Consultation response on Purpose Codes in ISO 20022 Payment Messaging. When SWIFT retires MT messaging for payments (currently expected in November 2025), we will mandate the use of structured remittance for pacs.008 payments. In line with international standards, we will enable hybrid addresses from November 2025, and reject fully unstructured addresses from November 2026.

We have continued our close collaboration with Pay.UK on implementing ISO 20022 messaging standards to ensure interoperability between CHAPS and the retail payment systems operated by Pay.UK where appropriate. In particular, to facilitate the introduction of Purpose Codes, the Bank and Pay.UK have jointly developed a UK recommended list of Purpose Codes.

For more detail on the Bank's updated policy timelines on enhanced data, please see our Policy Statement: Mandating ISO 20022 Enhanced data in CHAPS.

Market Guidance

The Bank’s approach to working with industry to develop ISO 20022 Market Guidance was outlined in our Policy Statement: Implementing ISO 20022 Enhanced data in CHAPS.

• On 14 April 2021, the Bank published the first Market Guide: Implementing ISO 20022 messaging in CHAPS covering property payments.
• On 3 February 2022, the Bank then published the second Market Guide for the corporate market sector.

These guidance documents have been commissioned independently on behalf of the Bank, based on engagement with industry. The Bank will continue working with industry stakeholders to define market best practice guidance for implementing the ISO 20022 messaging standard in order to realise the benefits of enhanced data, including through our Enhanced Data Working Group for CHAPS Direct Participants.

Note these Market Guidance publications are static documents so please check dates with this ISO 20022 Handbook.

6. Euro Liquidity Bridge – Change for CHAPS direct participants ahead of ISO 20022 migration

As operator of CHAPS, the Bank offers and operates a ‘Euro Liquidity Bridge’ which allows CHAPS Direct Participants (DPs) to use Euro cash sent to the Bank via TARGET2 as collateral to raise intraday Sterling liquidity in RTGS.

These procedures for use of this will be operated manually until the introduction of the new core ledger and settlement engine for RTGS. DPs will need to contact the Bank prior to funding the Bank’s Euro cash collateral account at DNB using their institution’s standard communication with the Bank for RTGS.

7. Participant and readiness testing

The Bank is providing a range of testing tools to participants as part of our CHAPS ISO 20022 transition, in order to support participant preparations.

MyStandards Readiness Portal

The MyStandards Readiness Portal allows users to validate their CHAPS payment messages against the published enhanced message schemas. All CHAPS Direct Participants are expected to make use of the MyStandards Readiness Portal. Indirect participants and software vendors can also access the portal via a Direct Participant.

Participant Test Simulator

The Test Simulator provides a solution for RTGS participants to receive inward test payment messages to themselves, removing the reliance on other participants. The Test Simulator is able to ingest and generate messages from bespoke message schemas built on industry standard ISO 20022 messages. 

For any queries on Participant Readiness and Testing, participants should contact RTGSReadiness@bankofengland.co.uk. 

8. Future maintenance for CHAPS and RTGS ISO 20022 messages

Before November 2025, the Bank will only make changes to the message schemas and Technical Guidance where such changes are critical. This is likely to be either:

• Where an error or ambiguity is evident and making an update to the documentation will provide a clear and significant benefit to users of the messages and/or the Bank; 
• Where international guidance has changed and the Bank needs to align its documentation in order to avoid a tangible risk to participants, the Bank, and/or wider industry.

From November 2025, we will implement a programme of regular upgrades to the CHAPS and RTGS messaging schemas. Our Change Management Framework sets out the yearly process for the maintenance of the CHAPS and RTGS message schemes and technical guidance. It is aligned as closely as possible with the change management processes for HVPS+ and Swift’s CBPR+ standards release cycles. 

In spring 2022, the Bank consulted with industry on a set of ambitious and innovative features that could be implemented in the renewed RTGS system, after the new core ledger settlement engine goes live. While work continues to develop these features, participants may see further guidance published by the Bank in future, potentially including new uses for existing or new ISO 20022 message types. More information, including the outcomes of the consultation can be found in the publication; Roadmap for Real-Time Gross Settlement service beyond 2024.

9. Previous documents