diff --git a/.github/workflows/adhoc.yml b/.github/workflows/adhoc.yml
index 1a71f66..3339ddf 100644
--- a/.github/workflows/adhoc.yml
+++ b/.github/workflows/adhoc.yml
@@ -15,7 +15,7 @@ jobs:
 
     env:
       FASTLANE_SKIP_UPDATE_CHECK: 1
-      DEVELOPER_DIR: /Applications/Xcode_15.3.app/Contents/Developer
+      DEVELOPER_DIR: /Applications/Xcode_15.4.app/Contents/Developer
 
     steps:
     - uses: actions/checkout@v4
diff --git a/.github/workflows/appstore.yml b/.github/workflows/appstore.yml
index ed21a58..14ff025 100644
--- a/.github/workflows/appstore.yml
+++ b/.github/workflows/appstore.yml
@@ -15,7 +15,7 @@ jobs:
 
     env:
       FASTLANE_SKIP_UPDATE_CHECK: 1
-      DEVELOPER_DIR: /Applications/Xcode_15.3.app/Contents/Developer
+      DEVELOPER_DIR: /Applications/Xcode_15.4.app/Contents/Developer
 
     permissions:
       contents: write
diff --git a/.github/workflows/renovate.yml b/.github/workflows/renovate.yml
index a15339d..0efcb50 100644
--- a/.github/workflows/renovate.yml
+++ b/.github/workflows/renovate.yml
@@ -57,7 +57,7 @@ jobs:
     if: needs.precheck.outputs.result == 'resolve'
 
     env:
-      DEVELOPER_DIR: /Applications/Xcode_15.3.app/Contents/Developer
+      DEVELOPER_DIR: /Applications/Xcode_15.4.app/Contents/Developer
 
     steps:
     - uses: Cyberbeni/install-swift-tool@v2
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 37b8198..46f1cdd 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: macos-14
 
     env:
-      DEVELOPER_DIR: /Applications/Xcode_15.3.app/Contents/Developer
+      DEVELOPER_DIR: /Applications/Xcode_15.4.app/Contents/Developer
 
     steps:
       - uses: actions/checkout@v4
diff --git a/README.md b/README.md
index 9604117..5f3c575 100644
--- a/README.md
+++ b/README.md
@@ -9,9 +9,9 @@ WebSocket Client for iOS
 ### Xcode
 
 ```command
-$ xcodebuild -verison
-Xcode 15.3
-Build version 15E204a
+$ xcodebuild -version
+Xcode 15.4
+Build version 15F31d
 ```
 
 ### Ruby