OCPP is an open protocol for communication between Charge Points and a Central System that quickly became the industry standard. Since OCPP 1.6 launched in 2015, the protocol has evolved through 2.0, 2.0.1, and now 2.1 — each version adding critical capabilities for modern EV charging networks. With OCPP 2.1 now adopted as international standard IEC 63584, choosing the right version is more consequential than ever. This guide compares all three major versions to help you decide which fits your infrastructure roadmap.

Open Charge Point Protocol powers EV charging stations

OCPP stands for Open Charge Point Protocol and was created by the Open Charge Alliance (OCA) in 2009. Today the global consortium promotes open standards with more than 220 participants from 43 countries on 5 continents. OCPP became the EV industry standard in just 6 years.

The Open Charge Point Protocol enables communication and data exchanges between electric vehicle charging points and central control systems — whether that system is called a CSMS, CPMS, or back-end platform.

As of 2026, most deployed EV chargers support OCPP 1.6, a growing number ship with OCPP 2.0.1, and the first OCPP 2.1 implementations are entering the field. Understanding the differences between these versions is essential for CPOs, hardware OEMs, and software providers planning their technology stack.

OCPP 1.6 – what made it revolutionary?

OCPP 1.6 was the first OCA protocol to gain worldwide recognition. It remains a solid, well-understood solution that covers most operational use cases deployed today.

The feature launched within OCPP 1.6 that reshaped EV charging was smart charging. It allowed sending Charging Profiles to the charging station — basically the foundation of today’s EV charging infrastructure. The Central System gains the ability to influence the charging power or current of a specific EV, or energy consumption on an entire Charge Point network.

Smart Charging has three typical use cases:

  • Load balancing — internal load management within the Charge Point that modulates the charging schedule per connector, staying within grid connection limits
  • Central smart charging — the Central System regulates charging schedules per transaction across the entire network
  • Local smart charging — a Local Controller manages energy distribution for a group of Charge Points (e.g., a parking garage) independently of the Central System

Key innovations in OCPP 1.6

  • Switch to JSON over WebSocket, reducing data usage and enabling OCPP communication through NAT routers
  • Extra statuses giving CPOs and EV drivers more information about charging state
  • Additional meter values for richer data reporting to the Central System
  • TriggerMessage allowing the Central System to request information from the Charge Point on demand
  • Modular implementation — functionalities can be adopted in steps

OCPP 2.0.1 – the security and architecture leap

OCPP 2.0 launched in April 2018, and OCPP 2.0.1 followed with important fixes discovered during Plugfests and field deployments. Version 2.0.1 is the production-ready release — no one should implement 2.0 directly.

OCPP 2.0.1 is a completely redesigned protocol with a different foundation than 1.6. It was built for bidirectional communication between a CSMS and a Charging Station, with a strong focus on security, device management, and ISO 15118 support. Because of these architectural changes, OCPP 1.6-compliant chargers cannot directly communicate via OCPP 2.0.1 — a firmware or hardware upgrade is required.

What OCPP 2.0.1 adds over 1.6

Device management

Inventory reporting, improved error and state reporting, and enhanced configuration. CPOs can decide how much information to monitor and collect, significantly reducing the cost of operating a Charging Station network.

Enhanced smart charging

Direct smart charging inputs from an Energy Management System (EMS) to a Charging Station, plus support for integrated smart charging across the CSMS, Charging Station, and EV. Local Controller smart charging was also improved.

Simplified transaction handling

One message for all transaction-related functionalities instead of over 10 separate messages. Combined with WebSocket compression, this reduces data overhead for large-scale deployments.

ISO 15118 support

The ISO 15118 standard for EVSE-to-EV communication enables Plug & Charge — automatic authentication and billing without RFID cards or apps.

Display and messaging support

Live tariff/price display on the charging station screen before, during, and after charging sessions.

Security profiles

Secure firmware updates, security logging, event notification, three security profiles for authentication (including client-side certificates), and mandatory TLS for communication.

OCPP 2.1 (IEC 63584) – the international standard

OCPP 2.1 represents a milestone: it has been adopted by the International Electrotechnical Commission as IEC 63584, making it the first OCPP version to become a formal international standard. This gives regulators, utilities, and procurement teams a standards-based reference they can mandate in tenders and grid codes.

Unlike the 1.6-to-2.0 jump, OCPP 2.1 builds incrementally on 2.0.1. Migration is significantly simpler — new features can be layered on top of an existing 2.0.1 implementation, and the protocol includes built-in version negotiation (falling back to 2.0.1 if one side doesn’t support 2.1).

Key additions in OCPP 2.1

V2G (Vehicle-to-Grid) bidirectional charging

Full ISO 15118-20 support enables bidirectional energy flow. EVs can feed energy back to the grid, participate in energy markets, or power a home (V2H). This positions EVs as distributed energy storage assets.

DER (Distributed Energy Resource) integration

Charging stations can now act as DERs, responding to grid signals via protocols like IEEE 2030.5. Utilities can control DER settings and curves through the CSMS, treating charging infrastructure as part of the grid.

Structured tariffs and local cost calculation

Tariff structures aligned with OCPI and OICP roaming protocols. Charging stations can display tariffs clearly and calculate session costs in real-time — critical for transparent pricing and regulatory compliance.

Local payments and prepaid support

Flexible payment integration via built-in terminals, external systems, or payment websites. Operators can set transaction limits (max cost, max energy) that work even in offline scenarios.

OCPP version comparison at a glance

Capability OCPP 1.6 OCPP 2.0.1 OCPP 2.1 (IEC 63584)
Transport JSON / SOAP over WebSocket JSON over WebSocket JSON over WebSocket
Smart charging Basic (profiles) Enhanced (EMS integration) Enhanced + DER curves
Security Optional TLS 3 security profiles, mandatory TLS Same as 2.0.1
ISO 15118 (Plug & Charge) Not supported ISO 15118-2 ISO 15118-2 + ISO 15118-20
V2G / bidirectional Not supported Not supported Full support
DER grid integration Not supported Not supported IEEE 2030.5 compatible
Transaction messages 10+ separate messages 1 unified message 1 unified message
Device management Basic Full inventory & monitoring Full inventory & monitoring
Payment integration RFID-based RFID + display tariffs RFID + local terminals + prepaid
Tariff transparency Limited Basic display Structured (OCPI/OICP aligned)
International standard No No Yes (IEC 63584)
Migration effort — Major (new architecture) Incremental from 2.0.1

Which OCPP version should you choose?

Start with OCPP 2.0.1 if you are building new infrastructure. The security improvements, simplified transaction handling, and ISO 15118 support make it the minimum viable protocol for any new deployment in 2026. OCPP 1.6 remains adequate for existing installations with no near-term plans for V2G or grid integration — but plan your migration path now.

Target OCPP 2.1 if your roadmap includes V2G, DER participation, or structured tariffs. Since 2.1 builds on 2.0.1 with backward compatibility, starting with 2.0.1 and upgrading to 2.1 is a low-risk strategy. The IEC 63584 standardization will increasingly appear in public tenders and utility requirements.

Codibly’s OCPP implementation experience spans all three versions. Our open-source OCPP accelerators can get you to production in weeks, whether you’re implementing 2.0.1 from scratch or adding 2.1 capabilities to an existing stack.