diff --git a/README.md b/README.md
index 07cc694..f1949e1 100644
--- a/README.md
+++ b/README.md
@@ -55,7 +55,7 @@ docker run --rm \
   -e FESS_ENDPOINT=https://your-fess-server \
   -e FESS_ACCESS_TOKEN=your_access_token_here \
   -e FESS_VERSION=15.9.0 \
-  ghcr.io/codelibs/fessctl:0.3.0 --help
+  ghcr.io/codelibs/fessctl:0.4.0 --help
 ```
 
 Run actual commands:
@@ -65,13 +65,13 @@ docker run --rm \
   -e FESS_ENDPOINT=https://your-fess-server \
   -e FESS_ACCESS_TOKEN=your_access_token_here \
   -e FESS_VERSION=15.9.0 \
-  ghcr.io/codelibs/fessctl:0.3.0 ping
+  ghcr.io/codelibs/fessctl:0.4.0 ping
 
 docker run --rm \
   -e FESS_ENDPOINT=https://your-fess-server \
   -e FESS_ACCESS_TOKEN=your_access_token_here \
   -e FESS_VERSION=15.9.0 \
-  ghcr.io/codelibs/fessctl:0.3.0 user list
+  ghcr.io/codelibs/fessctl:0.4.0 user list
 ```
 
 ### Method 3: Building Your Own Docker Image
diff --git a/pyproject.toml b/pyproject.toml
index ff6d115..175f13b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "fessctl"
-version = "0.4.0.dev0"
+version = "0.4.0"
 description = "CLI tool to manage Fess using the admin API"
 readme = "README.md"
 license = "Apache-2.0"
diff --git a/skills/fessctl/references/installation.md b/skills/fessctl/references/installation.md
index ddf88c1..97eca39 100644
--- a/skills/fessctl/references/installation.md
+++ b/skills/fessctl/references/installation.md
@@ -15,7 +15,7 @@ resolve_fessctl() {
   FESSCTL="docker run --rm \
     -e FESS_ENDPOINT -e FESS_ACCESS_TOKEN -e FESS_VERSION \
     --add-host=host.docker.internal:host-gateway \
-    ghcr.io/codelibs/fessctl:0.3.0"
+    ghcr.io/codelibs/fessctl:0.4.0"
 }
 
 resolve_fessctl
@@ -53,7 +53,7 @@ docker run --rm \
   -e FESS_ACCESS_TOKEN="$FESS_ACCESS_TOKEN" \
   -e FESS_VERSION="$FESS_VERSION" \
   --add-host=host.docker.internal:host-gateway \
-  ghcr.io/codelibs/fessctl:0.3.0 \
+  ghcr.io/codelibs/fessctl:0.4.0 \
   ping
 ```
 
diff --git a/skills/fessctl/references/troubleshooting.md b/skills/fessctl/references/troubleshooting.md
index 9aa418a..f748ca6 100644
--- a/skills/fessctl/references/troubleshooting.md
+++ b/skills/fessctl/references/troubleshooting.md
@@ -140,7 +140,7 @@ Recovery:
 
 ```bash
 docker login ghcr.io                         # if behind auth
-docker pull ghcr.io/codelibs/fessctl:0.3.0   # always name a release tag
+docker pull ghcr.io/codelibs/fessctl:0.4.0   # always name a release tag
 ```
 
 The tag is a **fessctl** release version, not a Fess version, and there is no `latest` — a bare `docker pull ghcr.io/codelibs/fessctl` therefore fails with `manifest unknown`. Which Fess server the container talks to is decided by `FESS_VERSION` at runtime, independently of the tag.
diff --git a/uv.lock b/uv.lock
index 1b79420..1d356f3 100644
--- a/uv.lock
+++ b/uv.lock
@@ -102,7 +102,7 @@ wheels = [
 
 [[package]]
 name = "fessctl"
-version = "0.4.0.dev0"
+version = "0.4.0"
 source = { editable = "." }
 dependencies = [
     { name = "httpx" },