What is the difference between OCPP 1.6 and 2.0.1?

OCPP 2.0.1 is not backward compatible with 1.6: transactions became configurable and unified, and the device model was added. OCPP 2.1 builds on 2.0.1 and keeps it compatible.

Explained in

OCPP in depth · Stop 03How do the OCPP versions differ?OCPP 1.6, 2.0.1 and 2.1 side by side: what changed, why 2.0.1 is not backward compatible, and which version supports which AFIR requirement.

OCPP 2.0.1 is not an incremental extension of 1.6; it is not backward compatible. Two changes made the break necessary:

From “Why 2.0.1 broke with 1.6”, stop 03

Terms

  1. OCPPOpen Charge Point Protocol: the open protocol between a charger and its operator's backend.
  2. Device modelOCPP 2.0.1's standard description of a charger's components and variables, for configuration and monitoring across manufacturers.
  1. Is a CSMS the same as a CPMS?Yes, both name the operator's backend. OCPP 1.6 calls it the Central System, OCPP 2.0.1 and 2.1 the charging station management system (CSMS); CPMS is the common industry term.
  2. How does a charger connect to the backend?The charger opens a WebSocket to its backend, announces itself and then checks in at a set interval. Commands from the backend travel over the same connection.
  3. How secure is OCPP?OCPP has three security profiles. Profile 2 adds TLS and a backend certificate, profile 3 certificates on both sides; profile 1 is not recommended for the field.
  4. Which OCPP messages make up a charging session?In OCPP 1.6: Authorize, StartTransaction, MeterValues and StopTransaction. In 2.0.1, the transaction messages are events of one type, TransactionEvent.
  1. Open Charge Alliance: What is new in OCPP 2.0.1? Whitepaper, version 1.0, March 2023. https://openchargealliance.org/wp-content/uploads/2024/01/new_in_ocpp_201-v10.pdf. Checked 09 Oct 2026. Licence: CC BY-ND 4.0.