Meter Values Section — Migration Guide

High-Level Overview

2.1 SignedMeterValueType Breaking

This is the most impactful schema change in this section. Two previously required fields are now optional.

{
  "signedMeterData": "...",   // required
  "signingMethod": "...",     // required
  "encodingMethod": "...",    // required
  "publicKey": "..."          // required
}

{
  "signedMeterData": "...",   // required (max 32768)
  "signingMethod": "...",     // OPTIONAL
  "encodingMethod": "...",    // required
  "publicKey": "..."          // OPTIONAL
}

2.2 LocationEnumType — New Value

2.3 MeterValuesRequest / MeterValuesResponse — customData

Both MeterValuesRequest and MeterValuesResponse gain an optional customData field in 2.1.

MeterValuesRequest:
{
  "evseId": 1,
  "meterValue": [...]
}

MeterValuesResponse:
{}

MeterValuesRequest:
{
  "evseId": 1,
  "meterValue": [...],
+ "customData": { "vendorId": "..." }
}

MeterValuesResponse:
{
+ "customData": { "vendorId": "..." }
}

2.4 UnitOfMeasureType

No structural changes. Both versions share the same schema (unit string max 20, multiplier integer, defaults Wh / 0).

2.5 ReadingContextEnumType

No changes. All 8 values remain identical across both versions.

2.6 PhaseEnumType

No changes. All 10 values remain identical across both versions.

OCPP 2.1 significantly expands the list of supported measurands. All 2.0.1 measurands are retained. The following are new in 2.1.

Energy Measurands (New)

Power Measurands (New)

Current Measurands (New)

Voltage Measurands (New)

Display Measurands New category

EnergyRequest Measurands New category

The following trigger reasons are new in 2.1:

Trigger reasons retained from 2.0.1: Authorized, CablePluggedIn, ChargingRateChanged, ChargingStateChanged, Deauthorized, EVCommunicationLost, EVConnectTimeout, EVDeparted, EVDetected, MeterValueClock, MeterValuePeriodic, RemoteStart, RemoteStop, ResetCommand, StopAuthorized, Trigger, UnlockCommand.

5.1 New Top-Level Fields

{
  "eventType": "...",
  "timestamp": "...",
  "triggerReason": "...",
  "seqNo": 0,
  "transactionInfo": {...},
  "meterValue": [...],
  "evse": {...},
  "idToken": {...},
  "offline": false
}

{
  "eventType": "...",
  "timestamp": "...",
  "triggerReason": "...",
  "seqNo": 0,
  "transactionInfo": {...},
  "meterValue": [...],
  "evse": {...},
  "idToken": {...},
  "offline": false,
+ "numberOfPhasesUsed": 3,
+ "cableMaxCurrent": 32,
+ "reservationId": 123,
+ "costDetails": {...},
+ "preconditioningStatus": "Ready",
+ "evseSleep": false,
+ "customData": {...}
}

5.2 TransactionType — New Fields

{
  "transactionId": "...",
  "chargingState": "...",
  "timeSpentCharging": 300,
  "stoppedReason": "..."
}

{
  "transactionId": "...",
  "chargingState": "...",
  "timeSpentCharging": 300,
  "stoppedReason": "...",
+ "remoteStartId": 42,
+ "operationMode": "ChargingOnly",
+ "tariffId": "tariff-abc-123",
+ "transactionLimit": {
+   "maxCost": 50.00,
+   "maxEnergy": 60000,
+   "maxTime": 7200,
+   "maxSoC": 80
+ }
}

5.3 StoppedReasonEnumType — New Value New

All existing stoppedReason values remain unchanged.

New Field: transactionLimit Extended

{
  "totalCost": 12.50,
  "chargingPriority": 0,
  "idTokenInfo": {...},
  "updatedPersonalMessage": {...}
}

{
  "totalCost": 12.50,
  "chargingPriority": 0,
  "idTokenInfo": {...},
  "updatedPersonalMessage": {...},
+ "transactionLimit": {
+   "maxCost": 50.00,
+   "maxEnergy": 60000,
+   "maxTime": 7200,
+   "maxSoC": 80
+ },
+ "customData": {...}
}

J01 — Sending Meter Values Not Related to a Transaction

No functional changes to the flow. The core behavior (CS sends MeterValuesRequest, CSMS responds with MeterValuesResponse) remains identical.

All J01 requirements (J01.FR.02 through J01.FR.22) remain unchanged.

J02 — Sending Transaction Related Meter Values

The flow remains the same (CS sends TransactionEventRequest, CSMS responds with TransactionEventResponse), but the message payloads are expanded.

All other J02 requirements (J02.FR.02 through J02.FR.22) remain unchanged.

J03 — ISO 15118 Charging Loop with Metering Information Exchange

No functional changes. The CSMS handling remains transparent — treat identically to J02. The ISO 15118 metering exchange between EV and CS is unchanged.

J03.FR.04 remains unchanged.

New Variables in 2.1 New

Changed Variables (2.0.1 → 2.1)

In 2.0.1, upstream configuration was limited to aligned data only: AlignedDataCtrlr.UpstreamMeasurands and AlignedDataCtrlr.UpstreamInterval. In 2.1, upstream configuration is expanded to cover both sampled and aligned data with the four variables listed above.

Unchanged Variables

All other configuration variables remain the same across both versions:

Schema & Validation Updates

TransactionEventRequest Handling

TransactionEventResponse Construction

Configuration

Business Logic