It was our understanding the migration window was 25/04 - 26/10 however a recent communication from Npower stated a deadline of 26/12, was the deadline revised? Is it likely to be revised again?

There are multiple stages within the MHHS programme. 

The Migration window opens in April 2025 for Suppliers and Agents who have completed and qualified in their Systems Integration Testing (SIT), as they will have proven that their systems and MHHS processes are working correctly. This will be followed by Suppliers and Agents who are going through qualification from October 2025.

There is then a 12-month window until the beginning of October 2026 to complete all migrations.

The milestone after this is in December 2026, when the new MHHS Settlement model will come into effect. This new model will reduce the amount of time it takes the energy industry to balance the demand for energy with how much has been supplied down from 14 months to just 4 months.

We’ll be in touch about this closer to the time and you will be able to find out about this, and more, on our MHHS hub online.