The C# editor code and python trainer code are not compatible between releases. This means that if you upgrade one, you *must* upgrade the other as well. If you experience new errors or unable to connect to training after updating, please double-check that the versions are in the same.
The versions can be found in
* `Academy.k_ApiVersion` in Academy.cs ([example](https://github.com/Unity-Technologies/ml-agents/blob/b255661084cb8f701c716b040693069a3fb9a257/UnitySDK/Assets/ML-Agents/Scripts/Academy.cs#L95))
* `UnityEnvironment.API_VERSION` in environment.py ([example](https://github.com/Unity-Technologies/ml-agents/blob/b255661084cb8f701c716b040693069a3fb9a257/ml-agents-envs/mlagents/envs/environment.py#L45))
# Migrating
## Migrating from ML-Agents toolkit v0.11.0 to v0.12.0