Legacy Data Item API Service
Summary
MHHS removes certain Data Items (e.g. Profile Class, Measurement Class, Standard Settlement Configuration, Time Pattern Regime etc.) that are important to wider processes and products offered to consumers. This proposal is seeking a mechanism for electricity Market Participants to look up the previous entries for these legacy Data Items held before MHHS Migration begins.
Latest update and next planned activity
Date of latest update
Latest Update
02/06/2026 - the REC Change Panel voted to reject the implementation of this Change Proposal, in line with the Code Manager recommendation. The appeal window closed on 17 June 2026.
Impacts Overview
Impacted REC Parties and Market Participants
Data Collector
Data Services
Distribution Network Operator
Energy Supplier
Meter Operator Agent
Impacted REC Documents
Schedule 12 - Data Access
Impacted REC Services
Electricity Enquiry Service (EES)
Priority and rationale
Standard
Priority last updated on 17 Sep 2026
Solution development
Problem Statement
The risk of loss of certain Data Items for MHHS Migrated Metering Points may impact Parties in their ability to carry out and support industry processes, or in what products they are able to offer Consumers, in both the MHHS Market and following a Reverse Migration.
No documents available.
There is currently no Change Plan.
Original submission
Change details
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4 Nov 2025
Change details
Legacy Data Item API Service
MHHS removes certain data items (e.g. Profile Class, Measurement Class, Standard Settlement Configuration, Time Pattern Regime etc.) that are important to wider processes and products offered to consumers. This proposal is seeking a mechanism for electricity market participants to look up the last held entry for these legacy data items before MHHS migration begins.
Inefficient process (particularly around Reverse Migration for MHHS – can’t identify previous Measurement Class, Profile Class, SSC once migrated to MHHS), inability to offer certain products, unnecessary site visits and meter exchanges due to not knowing configurations supported by current meter.
REC receive a monthly snapshot of EES. A new service should be created that allows electricity market participants to query legacy data items (PC, SSC, TPR, MC etc.) from the last snapshot before MHHS Migration begins (September 2025).
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Impacts
No details provided
Billing accuracy, On site experience, Switching experience, Trust and confidence
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Schedule 12 - Data Access
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No details provided
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Electricity Enquiry Service (EES) Service Definition
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Data Access Matrix
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EES API Technical Specification
Either update to existing EES API or an new API spec.
No details provided
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Data Collectors, Data Services, Distribution Network Operators, Energy Suppliers, Meter Operator Agent
Enables electricity market participants to view legacy data items pre-MHHS Migration.
No details provided
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No details provided
Priority & timing
No
Yes – MHHS Migration began on 22/10/25 so accessing legacy data items for MHHS migrated MPANs will become increasingly necessary as the opportunities for reverse migration etc. increase.
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No details provided
Billing accuracy, On site experience, Switching experience, Trust and confidence