OCPP 1.6 vs 2.0.1: Differences, Features, and Migration Guide

OCPP 1.6 and OCPP 2.0.1 are the two active versions of the Open Charge Point Protocol. OCPP 1.6 is deployed on the vast majority of charge points worldwide (estimated 80%+ of installed base as of 2025), while OCPP 2.0.1 is the standard for new deployments requiring advanced security, ISO 15118 Plug & Charge, and grid-integrated smart charging.

Most production CSMS platforms need to support both versions simultaneously, since operators typically manage mixed fleets of legacy and modern charge points.

If you need version-specific validation guidance, start with OCPP 1.6 testing and OCPP 2.0.1 testing.

If you are deciding how to support both versions in one backend, continue with CSMS testing or see platform features.

Quick Comparison: OCPP 1.6 vs 2.0.1

Security: The Biggest Difference

Security is the single most significant improvement in OCPP 2.0.1. In OCPP 1.6, TLS encryption is optional — many production deployments run unencrypted WebSocket connections, relying solely on network-level security.

OCPP 1.6 Security

• TLS is optional and often not implemented
• No standardized authentication mechanism
• No certificate management
• No signed firmware updates
• Vulnerable to man-in-the-middle attacks on unencrypted connections

OCPP 2.0.1 Security Profiles

OCPP 2.0.1 defines three mandatory security profiles:

Profile 3 provides the strongest security: the charger and CSMS authenticate each other with X.509 certificates, preventing unauthorized devices from connecting. OCPP 2.0.1 also adds:

• Signed firmware updates: Cryptographic verification prevents malicious firmware
• Secure boot: Ensures only authorized firmware runs on the charge point
• Certificate lifecycle management: Install, update, and revoke certificates remotely

Smart Charging Comparison

Smart charging capabilities differ substantially between versions.

OCPP 1.6 Smart Charging

OCPP 1.6 supports SetChargingProfile with basic schedule periods. Each profile contains a stack level and a sequence of time-based power limits.

Limitations:

• Profiles apply per connector only
• No station-wide power distribution
• No external constraint handling (grid operator limits)
• No composite schedule calculation on the charger
• Basic priority system (stack levels 0-99)

OCPP 2.0.1 Smart Charging

OCPP 2.0.1 introduces composite schedules and a hierarchical profile system:

• Charging Station profiles: Apply power limits to the entire station
• EVSE profiles: Apply limits per EVSE (charging point)
• Transaction profiles: Apply limits per active session
• External constraints: Grid operator limits override local profiles
• Composite schedules: Charger calculates the effective schedule from all active profiles
• Cost-based optimization: Charge when electricity is cheapest

ISO 15118 and Plug & Charge

ISO 15118 is the standard for high-level communication between EVs and chargers, enabling Plug & Charge — where the vehicle authenticates automatically when plugged in, with no RFID card or app needed.

OCPP 1.6 has no native ISO 15118 support. Some implementations use the DataTransfer message as a workaround, but this is non-standard and inconsistent across vendors.

OCPP 2.0.1 provides full ISO 15118 integration:

• Certificate-based vehicle authentication
• Contract certificate installation and updates
• Signed metering data for billing accuracy
• Vehicle-to-Grid (V2G) communication support

If your roadmap includes Plug & Charge, OCPP 2.0.1 is required.

Transaction Handling

OCPP 1.6

Transactions follow a simple Start/Stop model:

1. StartTransaction.req → CSMS assigns a transaction ID
2. MeterValues sent periodically during charging
3. StopTransaction.req → Transaction ends

Problem: If the charger loses connectivity between Start and Stop, the transaction can become orphaned. Recovery requires manual intervention or custom workarounds.

OCPP 2.0.1

Transactions use an event-driven model:

1. TransactionEvent(Started) → New transaction
2. TransactionEvent(Updated) → Meter values, status changes
3. TransactionEvent(Ended) → Transaction complete

Key improvement: Each event is independently transmitted and can be queued offline. When connectivity is restored, events are sent in order. The CSMS can reconstruct the complete transaction from the event stream, eliminating orphaned transactions.

Device Management

OCPP 1.6

Device configuration uses key-value pairs via GetConfiguration and ChangeConfiguration. There are approximately 50 standardized configuration keys, with vendors often adding proprietary extensions.

OCPP 2.0.1

The comprehensive Device Model replaces configuration keys with a structured variable system:

• Components: Logical parts of the charger (Connector, EVSE, Controller)
• Variables: Attributes of each component (CurrentLimit, Temperature, FirmwareVersion)
• Characteristics: Metadata about each variable (read-only, writable, data type, unit)

This provides 500+ standardized variables covering every aspect of charger configuration, monitoring, and diagnostics. The device model makes it possible to manage any charger without vendor-specific documentation.

Message Types Comparison

Messages Only in OCPP 2.0.1

Messages in Both Versions (with improvements in 2.0.1)

When to Use Which Version

Choose OCPP 1.6 if:

• You need maximum compatibility with existing chargers
• Your network consists primarily of AC Level 2 chargers
• ISO 15118 Plug & Charge is not on your roadmap
• You need to ship a working product quickly on a budget

Choose OCPP 2.0.1 if:

• Security is a top priority (regulatory or enterprise requirements)
• You need ISO 15118 Plug & Charge support
• You're building a new platform from scratch
• You need advanced smart charging for grid integration
• You're deploying DC fast chargers with complex billing
• You want future-proof architecture

Best Practice: Support Both

Most modern CSMS platforms support OCPP 1.6 and 2.0.1 simultaneously. A typical production network has:

• Legacy AC chargers on OCPP 1.6
• New DC fast chargers on OCPP 2.0.1
• The CSMS handles protocol translation internally

Migration Guide: OCPP 1.6 to 2.0.1

Step 1: Assess Your Current Implementation

Audit your OCPP 1.6 message handlers. Map each handler to its 2.0.1 equivalent:

• StartTransaction / StopTransaction → TransactionEvent
• GetConfiguration / ChangeConfiguration → GetVariables / SetVariables
• MeterValues → Embedded in TransactionEvent(Updated)

Step 2: Implement the Device Model

The device model is the biggest architectural change. You'll need:

• A database schema for Components, Variables, and their Characteristics
• Handlers for GetBaseReport, NotifyReport, GetVariables, SetVariables
• A mapping layer from your existing configuration to the device model

Step 3: Migrate Transaction Handling

Replace Start/Stop transaction logic with the event-driven model:

• Handle TransactionEvent with Started, Updated, and Ended types
• Implement event sequencing and offline event replay
• Update your billing system to work with event streams

Step 4: Add Security Profiles

Implement at least Security Profile 2 (TLS with server certificate):

• Configure your WebSocket server for TLS
• Implement HTTP Basic Auth over TLS
• Set up certificate management for Profile 3

Step 5: Test Thoroughly

Testing the migration is critical. You need to validate:

• Both protocol versions running simultaneously
• Backward compatibility with existing 1.6 chargers
• All new 2.0.1 message flows
• Security profile negotiation
• Smart charging composite schedules

OCPPLab lets you run OCPP 1.6 and 2.0.1 virtual chargers side by side, test migration scenarios, and validate all error handling paths without physical hardware.

How to Test Both OCPP Versions

Validating an OCPP implementation across both versions requires hundreds of test cases covering message flows, error scenarios, edge cases, and version-specific features. Physical charger testing is impractical at this scale.

OCPPLab provides:

• Side-by-side OCPP 1.6 and 2.0.1 virtual chargers
• 100+ pre-built device model profiles from real charger vendors
• Automated test suites covering all message types in both versions
• Security profile testing (Profile 1, 2, and 3)
• Smart charging composite schedule validation
• Load testing with 10,000+ concurrent connections across both versions

Start your free simulation and test both OCPP versions in minutes.

Frequently Asked Questions

Can a CSMS support both OCPP 1.6 and 2.0.1 simultaneously?

Yes, and most production CSMS platforms do. The CSMS detects the protocol version during the WebSocket handshake (via the Sec-WebSocket-Protocol header) and routes messages to the appropriate handler. This is essential since real-world networks have mixed fleets.

Is OCPP 2.0.1 backward compatible with 1.6?

No. OCPP 2.0.1 is a major protocol revision with different message structures, a new device model, and event-driven transactions. A charger running 1.6 cannot communicate with a CSMS that only supports 2.0.1, and vice versa. The CSMS must implement both versions independently.

Which OCPP version do new chargers support?

As of 2025, most new commercial chargers support both OCPP 1.6 and 2.0.1. Many ship with 1.6 as the default and offer 2.0.1 via firmware update. DC fast charger manufacturers (ABB, Tritium, Kempower) generally have stronger 2.0.1 support than AC charger manufacturers.

When will OCPP 1.6 be deprecated?

The Open Charge Alliance has not announced a deprecation date for OCPP 1.6. Given the massive installed base, 1.6 will remain relevant for many years. However, new deployments are increasingly moving to 2.0.1, and OCA's focus is on the 2.x line.

What is OCPP 2.1?

OCPP 2.1 is the next minor version after 2.0.1, adding features for ISO 15118-20 (bidirectional charging / V2G), improved smart charging, and better tariff handling. It maintains backward compatibility with 2.0.1 chargers for core functionality.

How many message types does each version have?

OCPP 1.6 defines approximately 30 message types. OCPP 2.0.1 defines over 50 message types, with the additions primarily covering the device model, certificate management, ISO 15118, and display messages.

Is OCPP 2.0.1 harder to implement than 1.6?

Yes. OCPP 2.0.1 has a larger specification, more message types, mandatory security requirements, and the complex device model. A typical 2.0.1 implementation takes 2-3x longer than 1.6. However, the result is significantly more robust and future-proof.

What is the difference between OCPP and OCPI?

OCPP manages communication between a charger and its management system (CSMS). OCPI manages roaming between different charging networks, allowing drivers to use any network with a single account. They serve different purposes and are typically both needed in a production charging network.