Baselined Interim Release 5, 5.1, 5.2, 5.3, 5.4 and 5.5 Design Artefacts
Please note that as of 1 September 2025, the MHHS Programme Design mailbox, Design artefacts and the Design Issues Notification (DIN) log on the MHHS website are no longer monitored or updated. They are retained for historical reference only.
Following Milestone 8 (M8), the Target Operating Model (TOM) and MHHS Design were fully codified, and the Code Bodies no longer maintain standalone Programme artefacts. The live Code and Code Subsidiary Documents are now the single source of truth, and any changes made through Code governance will not appear in the historical documents.
You can view the latest artefacts online, directly from the respective Code Bodies websites, listed below:
Balancing & Settlement Code (BSC)
Retail Energy Code (REC)
Distribution Connection and Use of System Agreement (DCUSA)
For the latest information or to raise queries, please use the Elexon Support Portal or contact the respective Code Bodies directly.
You can view the historical Baselined Design Artefacts for Interim Release 5, 5.1, 5.2, 5.3, 5.4 and 5.5 in the respective libraries below.
We have listed these Artefacts in their own libraries to support participant engagement with the Artefacts.
Baselined Interim Release 5.5 Design Artefacts
On 3 April 2024, the Programme published Interim Release 5.5 Design Artefacts.
Interim Release 5.5 incorporates changes to Swagger.
Full details of the issues addressed are covered in the Release Note below:
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Baselined Interim Release 5.4 Design Artefacts
On 7 February 2024, the Programme published Interim Release 5.4 Design Artefacts.
Interim Release 5.4 incorporates changes to Swagger and the DES-138 Interface Catalogue.
Full details of the issues addressed are covered in the Release Note below:
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Baselined Interim Release 5.3 Design Artefacts
On 17 January 2024, the Programme published Interim Release 5.3 Design Artefacts.
Interim Release 5.3 incorporates changes to Swagger and the E2E001 End to End Solution Architecture document.
Full details of the issues addressed are covered in the Release Note below:
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Baselined Interim Release 5.2 Design Artefacts
On 13 December 2023, the Programme published Interim Release 5.2 Design Artefacts.
Interim Release 5.2 incorporates changes to address Swagger and DES138 Interface Catalogue alignment.
Full details of the issues addressed are covered in the Release Note below:
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Baselined Interim Release 5.1 Design Artefacts
On 17 October 2023, the Programme published Interim Release 5.1 Design Artefacts.
Interim Release 5.1 incorporates changes to address Swagger and DES138 Interface Catalogue alignment.
Full details of the issues addressed are covered in the Interim Release 5.1 Release Note below:
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Baselined Interim Release 5 Design Artefacts
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