OCPP 1.6 vs 2.0.1 vs 2.1
The Open Charge Alliance currently publishes three OCPP versions. Pick the one your hardware and CSMS actually speak — then test that version, not a slide-deck claim.
OCA currently lists OCPP 1.6 (2015), OCPP 2.0.1 (2020, IEC 63584), and OCPP 2.1 (2025, IEC 63584-210). Download the official specification documents.
Open the OCPP simulator · 1.6J samples · 2.0.1 samples · OCPP 2.1
Quick comparison
| Topic | OCPP 1.6J | OCPP 2.0.1 | OCPP 2.1 |
|---|---|---|---|
| Released | 2015 | 2020 | 2025 |
| Official spec | OCA 1.6 | OCA 2.0.1, IEC 63584 | OCA 2.1, IEC 63584-210 |
| WebSocket subprotocol | ocpp1.6 | ocpp2.0.1 | ocpp2.1 |
| Session model | Start / Meter / Stop | TransactionEvent | 2.0.1 model + extra transaction options |
| Compatible with 1.6? | — | No | No |
| Test in Chargeflux | Yes | Yes | Planned |
Which version should you test first?
- Existing commercial fleets and most hardware still need solid OCPP 1.6J.
- New programmes, device management, and ISO 15118 paths need OCPP 2.0.1.
- V2X, DER, ISO 15118-20, and battery swap are OCPP 2.1 features — do not pretend a 2.0.1 station covers them.
If your CSMS claims dual-stack 1.6 + 2.0.1, run both simulators. Mapping 1.6 StartTransaction onto 2.0.1 TransactionEvent in one handler is a common production bug.
Same product, other stack: open the simulator and switch protocol to OCPP 2.0.1.
Sample-message guides
FAQ
Which OCPP versions does the Open Charge Alliance support?
Three current versions: OCPP 1.6 (2015), OCPP 2.0.1 (2020, IEC 63584), and OCPP 2.1 (2025, IEC 63584-210). Older 1.2/1.5 stacks are no longer supported by OCA.
Is OCPP 2.0.1 backward compatible with OCPP 1.6?
No. OCA states they are not compatible. Treat them as two integration surfaces.
Is OCPP 2.1 compatible with OCPP 2.0.1?
OCA designed 2.1 so application logic written for 2.0.1 continues to work. 2.1 is not compatible with 1.6.
Which OCPP versions can I test in Chargeflux?
OCPP 1.6J and OCPP 2.0.1 today. OCPP 2.1 is on the public roadmap without a promised date.
Last reviewed August 2026 · Chargeflux.io