diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index a427788baf7b..8c20b0613498 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -3,7 +3,7 @@
   "google-ads-ad_manager+FILLER": "0.0.0",
   "google-ads-ad_manager-v1": "5.0.1",
   "google-ads-ad_manager-v1+FILLER": "0.0.0",
-  "google-ads-data_manager": "0.4.1",
+  "google-ads-data_manager": "0.4.2",
   "google-ads-data_manager+FILLER": "0.0.0",
   "google-ads-data_manager-v1": "0.8.0",
   "google-ads-data_manager-v1+FILLER": "0.0.0",
diff --git a/google-ads-data_manager/CHANGELOG.md b/google-ads-data_manager/CHANGELOG.md
index 7e5606e64372..f95394a81469 100644
--- a/google-ads-data_manager/CHANGELOG.md
+++ b/google-ads-data_manager/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+### 0.4.2 (2026-08-11)
+
+#### Documentation
+
+* Onboard to Librarian & Update README ([#36214](https://github.com/googleapis/google-cloud-ruby/issues/36214)) 
+
 ### 0.4.1 (2026-08-05)
 
 #### Bug Fixes
diff --git a/google-ads-data_manager/lib/google/ads/data_manager/version.rb b/google-ads-data_manager/lib/google/ads/data_manager/version.rb
index f0dfc118524b..d97cd27b9ddf 100644
--- a/google-ads-data_manager/lib/google/ads/data_manager/version.rb
+++ b/google-ads-data_manager/lib/google/ads/data_manager/version.rb
@@ -20,7 +20,7 @@
 module Google
   module Ads
     module DataManager
-      VERSION = "0.4.1"
+      VERSION = "0.4.2"
     end
   end
 end
diff --git a/librarian.yaml b/librarian.yaml
index b8271d4f8133..52ef38f6e86e 100644
--- a/librarian.yaml
+++ b/librarian.yaml
@@ -39,7 +39,7 @@ libraries:
     apis:
       - path: google/ads/admanager/v1
   - name: google-ads-data_manager
-    version: 0.4.1
+    version: 0.4.2
     apis:
       - path: google/ads/datamanager/v1
     ruby: