diff --git a/.librarian/state.yaml b/.librarian/state.yaml
index 3f2bb6711767..3f7e41fab53f 100644
--- a/.librarian/state.yaml
+++ b/.librarian/state.yaml
@@ -1613,7 +1613,7 @@ libraries:
       - packages/google-cloud-dialogflow-cx
     tag_format: '{id}-v{version}'
   - id: google-cloud-discoveryengine
-    version: 0.15.0
+    version: 0.16.0
     last_generated_commit: c288189b43c016dd3cf1ec73ce3cadee8b732f07
     apis:
       - path: google/cloud/discoveryengine/v1
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0972a1008142..9d2462c36cfb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -83,7 +83,7 @@ Changelogs
 - [google-cloud-devicestreaming==0.2.0](https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-devicestreaming/CHANGELOG.md)
 - [google-cloud-dialogflow-cx==2.1.0](https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-dialogflow-cx/CHANGELOG.md)
 - [google-cloud-dialogflow==2.44.0](https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-dialogflow/CHANGELOG.md)
-- [google-cloud-discoveryengine==0.15.0](https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-discoveryengine/CHANGELOG.md)
+- [google-cloud-discoveryengine==0.16.0](https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-discoveryengine/CHANGELOG.md)
 - [google-cloud-dlp==3.33.0](https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-dlp/CHANGELOG.md)
 - [google-cloud-dms==1.13.0](https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-dms/CHANGELOG.md)
 - [google-cloud-documentai==3.7.0](https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-documentai/CHANGELOG.md)
diff --git a/packages/google-cloud-discoveryengine/CHANGELOG.md b/packages/google-cloud-discoveryengine/CHANGELOG.md
index dd6f92ee0d1d..d11f794f046d 100644
--- a/packages/google-cloud-discoveryengine/CHANGELOG.md
+++ b/packages/google-cloud-discoveryengine/CHANGELOG.md
@@ -4,6 +4,14 @@
 
 [1]: https://pypi.org/project/google-cloud-discoveryengine/#history
 
+## [0.16.0](https://github.com/googleapis/google-cloud-python/compare/google-cloud-discoveryengine-v0.15.0...google-cloud-discoveryengine-v0.16.0) (2025-12-17)
+
+
+### Features
+
+* auto-enable mTLS when supported certificates are detected ([d2b35b25342bfa389b472f9ce49922e630019fe6](https://github.com/googleapis/google-cloud-python/commit/d2b35b25342bfa389b472f9ce49922e630019fe6))
+* check Python and dependency versions in generated GAPICs ([d2b35b25342bfa389b472f9ce49922e630019fe6](https://github.com/googleapis/google-cloud-python/commit/d2b35b25342bfa389b472f9ce49922e630019fe6))
+
 ## [0.15.0](https://github.com/googleapis/google-cloud-python/compare/google-cloud-discoveryengine-v0.14.0...google-cloud-discoveryengine-v0.15.0) (2025-10-23)
 
 
diff --git a/packages/google-cloud-discoveryengine/google/cloud/discoveryengine/gapic_version.py b/packages/google-cloud-discoveryengine/google/cloud/discoveryengine/gapic_version.py
index 6b356a66811e..be6c08cee3cf 100644
--- a/packages/google-cloud-discoveryengine/google/cloud/discoveryengine/gapic_version.py
+++ b/packages/google-cloud-discoveryengine/google/cloud/discoveryengine/gapic_version.py
@@ -13,4 +13,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-__version__ = "0.15.0"  # {x-release-please-version}
+__version__ = "0.16.0"  # {x-release-please-version}
diff --git a/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1/gapic_version.py b/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1/gapic_version.py
index 6b356a66811e..be6c08cee3cf 100644
--- a/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1/gapic_version.py
+++ b/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1/gapic_version.py
@@ -13,4 +13,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-__version__ = "0.15.0"  # {x-release-please-version}
+__version__ = "0.16.0"  # {x-release-please-version}
diff --git a/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1alpha/gapic_version.py b/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1alpha/gapic_version.py
index 6b356a66811e..be6c08cee3cf 100644
--- a/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1alpha/gapic_version.py
+++ b/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1alpha/gapic_version.py
@@ -13,4 +13,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-__version__ = "0.15.0"  # {x-release-please-version}
+__version__ = "0.16.0"  # {x-release-please-version}
diff --git a/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1beta/gapic_version.py b/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1beta/gapic_version.py
index 6b356a66811e..be6c08cee3cf 100644
--- a/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1beta/gapic_version.py
+++ b/packages/google-cloud-discoveryengine/google/cloud/discoveryengine_v1beta/gapic_version.py
@@ -13,4 +13,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-__version__ = "0.15.0"  # {x-release-please-version}
+__version__ = "0.16.0"  # {x-release-please-version}
diff --git a/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1.json b/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1.json
index 061eb71645ed..e18088dc7e4c 100644
--- a/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1.json
+++ b/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1.json
@@ -8,7 +8,7 @@
     ],
     "language": "PYTHON",
     "name": "google-cloud-discoveryengine",
-    "version": "0.15.0"
+    "version": "0.16.0"
   },
   "snippets": [
     {
diff --git a/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1alpha.json b/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1alpha.json
index 8c60b426a4b1..57f9225e8d15 100644
--- a/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1alpha.json
+++ b/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1alpha.json
@@ -8,7 +8,7 @@
     ],
     "language": "PYTHON",
     "name": "google-cloud-discoveryengine",
-    "version": "0.15.0"
+    "version": "0.16.0"
   },
   "snippets": [
     {
diff --git a/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1beta.json b/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1beta.json
index 9c186ac39682..167301fc5c7c 100644
--- a/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1beta.json
+++ b/packages/google-cloud-discoveryengine/samples/generated_samples/snippet_metadata_google.cloud.discoveryengine.v1beta.json
@@ -8,7 +8,7 @@
     ],
     "language": "PYTHON",
     "name": "google-cloud-discoveryengine",
-    "version": "0.15.0"
+    "version": "0.16.0"
   },
   "snippets": [
     {