Compatibility Matrix

SDK and engine version compatibility for UndoLog.

Version compatibility

UndoLog follows semantic versioning. The engine and SDKs are versioned independently. This matrix shows which SDK versions work with which engine versions.

Python SDK

SDK Version	Engine Version	Status
0.1.x	0.1.x	Supported
0.2.x	0.1.x	Supported
0.2.x	0.2.x	Supported

TypeScript SDK

SDK Version	Engine Version	Status
0.1.x	0.1.x	Supported
0.2.x	0.1.x	Supported
0.2.x	0.2.x	Supported

Go Proxy

Proxy Version	Engine Version	Status
0.1.x	0.1.x	Supported
0.2.x	0.1.x	Supported
0.2.x	0.2.x	Supported

Compatibility rules

Patch versions are always compatible. SDK 0.1.0 works with engine 0.1.5. Engine 0.1.0 works with SDK 0.1.3.
Minor versions within 0.x are compatible. SDK 0.1.x works with engine 0.2.x if no breaking protobuf changes were introduced.
Major versions require matching major versions. SDK 1.0 requires engine 1.0 or later.
gRPC protocol version must match. The engine exposes undolog.v1 in the proto package. A future undolog.v2 proto would require SDK updates.

Breaking changes

A breaking change is any modification to:

gRPC service definitions or message types
Effect state machine transitions
Approval workflow semantics
Environment variable names or defaults
HTTP API request/response formats

Breaking changes are only introduced in major version bumps. Between major versions, the engine maintains backward compatibility with the previous two minor versions of each SDK.

Upgrade path

When upgrading across minor versions:

Check the changelog for breaking changes
Upgrade the engine first (it is backward compatible with older SDKs)
Upgrade SDKs after the engine is stable
Run the integration test suite to verify

When upgrading across major versions:

Read the migration guide in the changelog
Upgrade the engine and all SDKs together
Update any custom tool registrations or tier configurations
Run the full test suite