Add blog post for Open Workflow SDK Go v4.0.0 release

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ricardozanini

src/content/blog/releases/release-sdk-go-4.0.0.md

@@ -0,0 +1,90 @@
+---
+title: "Open Workflow SDK Go 4.0.0"
+author: "Ricardo Zanini"
+date: "2026-07-14"
+description: >-
+  Open Workflow SDK Go 4.0.0 is here — the Go SDK moves to its new home under the Open Workflow Specification organization with a fresh module path and updated branding.
+---
+
+## Announcing the Release of Open Workflow SDK Go 4.0.0
+
+We are excited to announce **Go SDK 4.0.0**, the first release under the **Open Workflow Specification** organization. This release marks the project's transition from "Serverless Workflow" to **Open Workflow**, reflecting the broader scope of the specification.
+
+👉 Full release notes: [GitHub – v4.0.0](https://github.com/open-workflow-specification/sdk-go/releases/tag/v4.0.0)
+
+---
+
+## What's New in 4.0.0?
+
+This release focuses on the rebranding — there are **no API or schema changes** from the v3.x line. The specification conformance remains at **v1.0.0**.
+
+### New GitHub Home
+
+The SDK now lives at [github.com/open-workflow-specification/sdk-go](https://github.com/open-workflow-specification/sdk-go). GitHub redirects from the old URL are in place, so existing links and references to v3.x releases continue to work.
+
+### Updated Go Module Path
+
+The module path has changed to reflect the new organization:
+
+```
+github.com/open-workflow-specification/sdk-go/v4
+```
+
+### Updated Error Type URIs
+
+Standard error type URIs now use the `open-workflow-specification.org` domain:
+
+```
+https://open-workflow-specification.org/spec/1.0.0/errors/validation
+https://open-workflow-specification.org/spec/1.0.0/errors/authentication
+...
+```
+
+---
+
+## Migration Guide
+
+Upgrading from v3.x is straightforward — update your imports and run `go get`:
+
+1. Update your import paths:
+
+   ```go
+   // Before
+   import "github.com/serverlessworkflow/sdk-go/v3/parser"
+   import "github.com/serverlessworkflow/sdk-go/v3/impl"
+
+   // After
+   import "github.com/open-workflow-specification/sdk-go/v4/parser"
+   import "github.com/open-workflow-specification/sdk-go/v4/impl"
+   ```
+
+2. Fetch the new module:
+
+   ```bash
+   go get github.com/open-workflow-specification/sdk-go/v4
+   ```
+
+3. If your code references error type URIs (e.g., `https://serverlessworkflow.io/spec/1.0.0/errors/...`), update them to `https://open-workflow-specification.org/spec/1.0.0/errors/...`.
+
+4. Run your tests to verify the transition:
+
+   ```bash
+   go test ./...
+   ```
+
+---
+
+## What's Next
+
+The reference implementation continues to grow. Check out the [implementation roadmap](https://github.com/open-workflow-specification/sdk-go#implementation-roadmap) to see what's supported and where you can contribute.
+
+---
+
+## Community
+
+The project remains under **CNCF** governance. Join us on the CNCF Slack in the `#open-workflow-sdk` channel to collaborate, ask questions, and contribute.
+
+* Issues & feedback: [github.com/open-workflow-specification/sdk-go/issues](https://github.com/open-workflow-specification/sdk-go/issues)
+* Specification: [github.com/open-workflow-specification/specification](https://github.com/open-workflow-specification/specification)
+
+Thank you to everyone who contributed to this milestone release!