M10/M11 Cutover Plan

The M10/M11 Cutover Plan sets out the activities that MHHS participants are required to carry out in the lead up to M10, at M10, and between M10 and M11 to enable the Programme to successfully reach both M10 and M11 respectively.

It outlines:

What these activities are
When they are expected to take place
Who the responsible parties are
The declaration requirements that participants are expected to follow
Key dependencies that may impact particular activities

In May 2025, the Programme received Participant Cutover plans from Licensed Distribution System Operators (LDSOs), Central Parties and Systems Integration Testing (SIT) Suppliers & Agents.

Following a review of these plans, the Programme published an updated consolidated Programme M10/M11 Cutover plan for consultation. This consultation closed on Friday 11 July 2025. Thank to you everyone who responded.

The M10/M11 Cutover Plan was baselined at the Migration & Cutover Advisory Group (MCAG) meeting on Tuesday 22 July 2025.

M10/M11 Cutover Plan v2.0

M10/M11 Consolidated Cutover Delivery Plan v2.0

The Programme is holding fortnightly engagement sessions with LDSOs on Wednesdays and M10/M11 Suppliers & Agents on Thursdays to enable participants to ask questions. If you'd like an invite to these sessions, please email PMO@mhhsprogramme.co.uk

In addition, those parties that receive feedback from the Programme on their Cutover Plans will be required to submit updated submissions as detailed in the Participant Cutover Plans section below.

Please note that this includes submitting an updated participant Cutover Plan template which has been updated to reflect the updated Cutover Plan.

If you have any questions, please email the Transition & Operational Readiness team at OpReadiness@mhhsprogramme.co.uk

M10/M11 Cutover Issue Form

As we progress through the cutover period, the Programme has developed a Cutover Issue Form to support identifying and resolving live, blocking issues.

This form is intended to be used only where a cutover activity is currently being blocked. If you are experiencing a problem or delay that is not actively preventing progress, please raise it via your M10 Cutover weekly reporting instead.

You can access the form below:

M10/M11 Cutover Issue Form

If you have any questions, please email Opreadiness@mhhsprogramme.co.uk

Cutover Consultation timelines and engagement

We've published details below outlining the engagement approach we're taking to the Cutover Plan.

If you have any questions, please email the Transition & Operational Readiness team at OpReadiness@mhhsprogramme.co.uk

M10/M11 Communications Approach

The Programme has published the M10/M11 Communications Approach, which provides a view of all planned communications activities and reporting requirements for the cutover period. This approach ensures that all industry participants are aligned and informed at each stage of the cutover period. You can view this document below:

M10/M11 Cutover Communications Approach

It includes detailed information on:

Participant reporting requirements
Communications to be issued and received throughout the cutover period
Guidance on self-declarations required from participants to support Programme decision making as set out within the M10/M11 Cutover Plan
The process for managing escalations during the period

During this period, reporting needs to be undertaken by Elexon, all LDSOs and those M10/M11 Suppliers & Agents that have been requested to develop and deliver cutover plans by the Programme.

The Programme has developed specific reporting templates for each constituency group, which you can find in the library below.

Please note that the first round of reporting is due at 15:00 on Wednesday 6 August 2025. Please share this with the Operational Readiness team at Opreadiness@mhhsprogramme.co.uk

If you have any questions, please also email Opreadiness@mhhsprogramme.co.uk

M10/M11 Reporting Templates - MHHS Cutover Communications Approach

Short Name	Doc Number	Theme	Version
M10.M11 Supplier Reporting Template - MHHS Cutover Communications Approach	MHHS-DEL4060	M10/M11 Reporting Template - MHHS Cutover Communications Approach	1.0
M10.M11 Agent Reporting Template - MHHS Cutover Communications Approach	MHHS-DEL4061	M10/M11 Reporting Template - MHHS Cutover Communications Approach	1.0
M10/M11 Elexon Reporting Template - MHHS Cutover Communications Approach	MHHS-DEL4062	M10/M11 Reporting Template - MHHS Cutover Communications Approach	1.0
M10/M11 LDSO Reporting Template - MHHS Cutover Communications Approach	MHHS-DEL4059	M10/M11 Reporting Template - MHHS Cutover Communications Approach	1.0

Participant Cutover Plans

As detailed through the Transition & Operational Readiness Working Group (TORWG), the Programme requested that Central Parties, Licensed Distribution System Operators (LDSOs), Systems Integration Testing (SIT) Suppliers and SIT Agents share a Cutover Plan with the Programme.

These plans outline the technical cutover activities that each participant must undertake to ensure that their systems are fully deployed, operational, and comply with the M10/M11 Cutover Plan deadlines, enabling the Programme to successfully meet both the M10 and M11 milestones.

The Programme has reviewed all Participant Cutover Plans and individual feedback was issued on Friday 27 June 2025. Participants were required to respond to the feedback that they receive through an updated submission, in line with the request below by Friday 11 July 2025.

You can view the Consolidated Programme M10/M11 Cutover Plan above on this page.

The deadline to submit updated participant plans was Friday 11 July 2025. Thank you to everyone who responded.

You can view the updated constituency group templates in the library below. 