diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 96f1cd9..4c313f9 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "1.3.0"
+  ".": "1.4.0"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1c3f22a..bd956d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## [1.4.0](https://github.com/googleapis/google-cloudevents-dotnet/compare/Google.CloudEvents.Protobuf-1.3.0...Google.CloudEvents.Protobuf-1.4.0) (2023-06-07)
+
+
+### Features
+
+* Generate extension attributes based on proto annotations ([db7afbc](https://github.com/googleapis/google-cloudevents-dotnet/commit/db7afbccc2f1277dcb281c38d01d509f7532e214))
+* Regenerate all code, including new events and extension attributes ([d219f8c](https://github.com/googleapis/google-cloudevents-dotnet/commit/d219f8c706589aa5305f03975f7fa7acc539a4bc))
+
 ## [1.3.0](https://github.com/googleapis/google-cloudevents-dotnet/compare/Google.CloudEvents.Protobuf-1.2.0...Google.CloudEvents.Protobuf-1.3.0) (2023-03-28)
 
 
diff --git a/src/ProductionProperties.xml b/src/ProductionProperties.xml
index c10885a..02f3d6a 100644
--- a/src/ProductionProperties.xml
+++ b/src/ProductionProperties.xml
@@ -3,7 +3,7 @@
 
   <!-- Version information -->
   <PropertyGroup>
-    <Version>1.3.0</Version>
+    <Version>1.4.0</Version>
   </PropertyGroup>
 
   <PropertyGroup>