diff --git a/RELEASING.md b/RELEASING.md
index 92f168481..0f3e17dbe 100644
--- a/RELEASING.md
+++ b/RELEASING.md
@@ -70,6 +70,18 @@ distinguishes it from a release.
    ```
    Pushing the tag triggers the publishing workflows (below).
 
+### Release candidates
+
+Release-candidate tags must include the same prerelease suffix in all four
+version fields. For example, before tagging `v2.1.0-rc0`, run
+`bash scripts/bump_version.sh 2.1.0-rc0`, refresh `backend/uv.lock` with
+`cd backend && uv lock`, and run `bash scripts/verify_versions.sh 2.1.0-rc0`
+from the repository root. Commit the version and lockfile changes before
+creating the tag. Python lockfiles normalize this version to `2.1.0rc0`;
+the source version fields checked by the release gate retain `2.1.0-rc0`.
+Re-running a failed workflow on an unchanged tag does not pick up a later
+version-fix commit.
+
 ## What CI publishes on a `v*` tag
 
 - `.github/workflows/container.yaml` — builds and pushes `backend`,
diff --git a/backend/pyproject.toml b/backend/pyproject.toml
index 291179bbc..9947cc63c 100644
--- a/backend/pyproject.toml
+++ b/backend/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "deer-flow"
-version = "2.1.0"
+version = "2.1.0-rc0"
 description = "LangGraph-based AI agent system with sandbox execution capabilities"
 readme = "README.md"
 requires-python = ">=3.12"
diff --git a/backend/uv.lock b/backend/uv.lock
index 7b79a8692..df324df1f 100644
--- a/backend/uv.lock
+++ b/backend/uv.lock
@@ -803,7 +803,7 @@ wheels = [
 
 [[package]]
 name = "deer-flow"
-version = "2.1.0"
+version = "2.1.0rc0"
 source = { virtual = "." }
 dependencies = [
     { name = "bcrypt" },
diff --git a/deploy/helm/deer-flow/Chart.yaml b/deploy/helm/deer-flow/Chart.yaml
index 24d445e58..e92bc355f 100644
--- a/deploy/helm/deer-flow/Chart.yaml
+++ b/deploy/helm/deer-flow/Chart.yaml
@@ -2,8 +2,8 @@ apiVersion: v2
 name: deer-flow
 description: DeerFlow — LangGraph-based AI super-agent (gateway + frontend + nginx + sandbox provisioner) deployed to Kubernetes.
 type: application
-version: 2.1.0
-appVersion: "2.1.0"
+version: 2.1.0-rc0
+appVersion: "2.1.0-rc0"
 keywords:
   - deerflow
   - langgraph
diff --git a/frontend/package.json b/frontend/package.json
index 626efa6ce..4547f1399 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,6 +1,6 @@
 {
   "name": "deer-flow-frontend",
-  "version": "2.1.0",
+  "version": "2.1.0-rc0",
   "private": true,
   "type": "module",
   "scripts": {