Migration Pathways for Non-SIT participants

What are Migration Pathways?

Qualification Testing (QT) progress across the Qualification Waves has demonstrated that many Non-Systems Integration Testing (SIT) participants either have, or plan to complete QT and submit their Test Completion Reports (TCR) before Wave Qualification Test deadlines as set out in Annex C of the Qualification Approach & Plan (QA&P) and Programme Plan. You can view the QA&P on the Qualification Approach & Plan page of this website.

In line with the principle that Non-SIT participants should progress through the Qualification process as fast as possible, the Code Bodies and the Programme have collaborated to develop a series of Migration Pathways.

The Migration Pathways intend to support those Non-SIT participants who can complete the Qualification process faster than the dates in Annex C of the QA&P and Programme Plan. They set out the dates by which Qualification and Service Activation activities must be completed by to hit a Target Migration start date. This in turn might support some participants to start Migration execution sooner than they expected.

These Migration Pathways:

Build on the Non-SIT Supplier & Agent End-to-End (E2E) Journey Maps
Set out the deadline dates a Non-SIT participant need to hit to qualify at the 12 Balancing & Settlement Code (BSC) Performance Assurance Boards (PABs) and/or Retail Energy Code (REC) Manager approval points
Show which Industry Standing Data (ISD) / Market Domain Data (MDD) publication a Non-SIT participant would be included in, depending on when they are qualified by the Code Bodies

The Pathways cover the full journey from Qualification Test completion through Service Activation and into the start of Migration execution. Service Activation activities include Data Integration Platform (DIP) onboarding to Production, agreement of a participant’s Effective From Date (EFD), and the publication and loading of ISD.

They provide clarity on the milestone dates, approval points and ISD / MDD publication cycles that need to align to begin Migration execution.

Next steps

Thank you to all Programme participants who responded to the recent End-to-End (E2E) Participant Journey, Migration Pathways and ISD Publish Programme Participant Information Request (PPIR). You can view more information on this PPIR on the Previous PPIRs page of this website.

The Programme, Code Bodies and the Elexon ISD team have reviewed and analysed all responses.

As a result:

Code Bodies have confirmed Migration Pathways directly with all participants.
The Migration Control Centre (MCC) has contacted Suppliers who indicated that they wish to change their Migration Start Date, providing guidance on how to make this update.
Elexon’s ISD team confirmed at the March 2026 Supplier Volume Allocation Group (SVG) meeting that the updated ISD Release Schedule has been approved to support MHHS migration pathways. This introduces six additional ISD-only publication cycles for MHHS-qualified Suppliers, enabling Suppliers to progress migration activities in a timely manner.
An update was shared at the Qualification and End-to-End (E2E) Sandbox Working Group (QWG) on 10 March 2026.

If you have any questions about this, please email the Programme Party Coordinator (PPC) team at PPC@mhhsprogramme.co.uk

Helpful information: EFD, Migration Start and ISD / MDD publications

The Migration Pathways table shows the relationship between a participants’ Effective From Date (EFD), Migration Start and the ISD and MDD publications. We encourage participants to use the E2E Journey Maps to understand how this applies in practice, which you can view on the Non-SIT Supplier & Agent Journey to Go-Live page of this website.

The points below provide some factors you need to consider when setting your EFD, Migration Start date and determining which ISD and MDD publications you’ll be included in:

A Supplier’s Migration Start Date can be on the same day as or after their EFD and DIP onboarding must be complete before the EFD.
The Migration Control Centre (MCC) advise leaving one day between the EFD and Migration Start Date as contingency. This is guidance rather than a requirement.
An EFD does not need to be on the same day as the ISD / MDD publication go-live date in which you are first included. This is why the table in the PPIR Guidance shows a range of dates for EFD and Migration Start.
Suppliers must ensure that their Agents are included in an ISD and MDD publication at the same time or earlier than the one they’re being added to.

From a Supplier’s EFD, they can and must be able to start sending and receiving DIP messages. Any new connections will be established under MHHS arrangements and there will be no reverse migration if Suppliers gain an MHHS migrated Meter Point Administration Number (MPAN).

ISD and MDD publications also influence Migration timing

The updated ISD calendar has been added to the Migration Pathways table following SVG approval.

For participant’s ease we have created two Migration Pathway tables; one for Suppliers and one for Agents.

This is because Agents can only be included in ISD publications that align with an MDD publication, whereas Suppliers can be included in any ISD publication, regardless of whether there is an MDD publication or not. MDD publications will remain monthly.

Suppliers must ensure that their Agents have qualified before, or at the same time as them, if they are contracting with them. Suppliers cannot go live on their EFD, unless their Agents are also going live, at the same time or earlier.

Managing your Migration Pathway

If your plans change, including changes to Qualification timing or your intended Migration Start Date, it is important that you notify the relevant teams as early as possible.

The Programme, Code Bodies and Elexon actively track participant progress against agreed Migration Pathways to ensure that they are:

on course to Qualify
onboarded to the DIP
included in ISD / MDD and start migrating as per the dates in the Pathways

Any changes to Migration Start Dates must be managed through Sprint Planning. Suppliers cannot change their Migration Start Date after the Sprint Planning cycle ahead of the Sprint in which they are due to start Migration, as they will have submitted a committed Migration Plan for that Sprint. Changes before this point may require engagement with the Programme and Code Bodies to confirm continued alignment across governance and publication milestones. For more information, please visit the Migration Sprints page of this website.

A participant’s intended go-live EFD should be communicated to Elexon's Customer On/Offboarding team in advance of the Fast Track Change Request (CR) Deadline of the MDD/ISD version they will be included in. This ensures that it can be processed in time for that version.

Please note: the Fast Track CR deadline is approximately one month before the relevant ISD / MDD version’s go-live date. If there are any changes to the EFD after the fast-track deadline but before the publish, participants should contact Elexon as soon as possible to discuss the feasibility of getting any last-minute updates made before the publish. However, there is no guarantee of this though, so this should be avoided where possible. Click here to view the MDD/ISD calendar on the Elexon website.

The Migration Pathways set out dates that participants are expected to meet to facilitate specific Qualification and Migration start dates. While participants are encouraged to start Migration as soon after Qualification as possible, there are scenarios where a participant may be able to accelerate their Qualification activities but are unable to change their go live/migration plans. In these scenarios participants may end up following an earlier migration pathway to their Target Performance Assurance Board (PAB)/Qualification date, while still tracking on a later pathway for their EFD/Migration Start Date. Participants are encouraged to discuss their individual Qualification journeys with their Qualification Analyst throughout the process to identify any opportunities to meet an earlier PAB date and help to de-risk their go live. 

Early notification supports effective coordination and helps avoid downstream impacts to Migration scheduling and industry data publications.

Need support?

If you have any queries about your individual Qualification journey, please email the Code Bodies at MHHSQualification@elexon.co.uk

If you have any questions about your individual Migration journey, please email the MCC team at Migration@mhhsprogramme.co.uk

If you have any queries about ISD, please email Elexon at mddc@elexon.co.uk