diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4384a01123..75880d30e5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog
 
+### [2.1.5](https://www.github.com/googleapis/java-core/compare/v2.1.4...v2.1.5) (2021-09-21)
+
+
+### Dependencies
+
+* downgrading protobuf to 3.17.3 ([#562](https://www.github.com/googleapis/java-core/issues/562)) ([5711b83](https://www.github.com/googleapis/java-core/commit/5711b835a19238df1bfa1f2e4dfc115495a55c9b))
+
 ### [2.1.4](https://www.github.com/googleapis/java-core/compare/v2.1.3...v2.1.4) (2021-09-15)
 
 
diff --git a/google-cloud-core-bom/pom.xml b/google-cloud-core-bom/pom.xml
index 515fe06cb7..9d325419ca 100644
--- a/google-cloud-core-bom/pom.xml
+++ b/google-cloud-core-bom/pom.xml
@@ -3,7 +3,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-core-bom</artifactId>
-  <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+  <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
   <packaging>pom</packaging>
   <parent>
     <groupId>com.google.cloud</groupId>
@@ -63,17 +63,17 @@
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-core</artifactId>
-        <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+        <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
       </dependency>
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-core-grpc</artifactId>
-        <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+        <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
       </dependency>
       <dependency>
         <groupId>com.google.cloud</groupId>
         <artifactId>google-cloud-core-http</artifactId>
-        <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+        <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
       </dependency>
     </dependencies>
   </dependencyManagement>
diff --git a/google-cloud-core-grpc/pom.xml b/google-cloud-core-grpc/pom.xml
index 808d9d3ef7..0b0b05383f 100644
--- a/google-cloud-core-grpc/pom.xml
+++ b/google-cloud-core-grpc/pom.xml
@@ -3,7 +3,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-core-grpc</artifactId>
-  <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+  <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
   <packaging>jar</packaging>
   <name>Google Cloud Core gRPC</name>
   <url>https://github.com/googleapis/java-core</url>
@@ -13,7 +13,7 @@
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-core-parent</artifactId>
-    <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+    <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
   </parent>
   <properties>
     <site.installationModule>google-cloud-core-grpc</site.installationModule>
diff --git a/google-cloud-core-http/pom.xml b/google-cloud-core-http/pom.xml
index 4ba4926b84..71fc59eb4d 100644
--- a/google-cloud-core-http/pom.xml
+++ b/google-cloud-core-http/pom.xml
@@ -3,7 +3,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-core-http</artifactId>
-  <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+  <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
   <packaging>jar</packaging>
   <name>Google Cloud Core HTTP</name>
   <url>https://github.com/googleapis/java-core</url>
@@ -13,7 +13,7 @@
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-core-parent</artifactId>
-    <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+    <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
   </parent>
   <properties>
     <site.installationModule>google-cloud-core-http</site.installationModule>
diff --git a/google-cloud-core/pom.xml b/google-cloud-core/pom.xml
index 96581586a3..a07fe21490 100644
--- a/google-cloud-core/pom.xml
+++ b/google-cloud-core/pom.xml
@@ -3,7 +3,7 @@
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-core</artifactId>
-  <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+  <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
   <packaging>jar</packaging>
   <name>Google Cloud Core</name>
   <url>https://github.com/googleapis/java-core</url>
@@ -13,7 +13,7 @@
   <parent>
     <groupId>com.google.cloud</groupId>
     <artifactId>google-cloud-core-parent</artifactId>
-    <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+    <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
   </parent>
   <properties>
     <site.installationModule>google-cloud-core</site.installationModule>
diff --git a/pom.xml b/pom.xml
index 8fc24826de..220a956f2f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-core-parent</artifactId>
   <packaging>pom</packaging>
-  <version>2.1.4</version><!-- {x-version-update:google-cloud-core:current} -->
+  <version>2.1.5</version><!-- {x-version-update:google-cloud-core:current} -->
   <name>Google Cloud Core Parent</name>
   <url>https://github.com/googleapis/java-core</url>
   <description>
@@ -159,7 +159,7 @@
     <google.api.version>1.32.1</google.api.version>
     <google.http.version>1.40.0</google.http.version>
     <grpc.version>1.40.1</grpc.version>
-    <protobuf.version>3.18.0</protobuf.version>
+    <protobuf.version>3.17.3</protobuf.version>
     <opencensus.version>0.28.0</opencensus.version>
     <annotations-api.version>1.3.2</annotations-api.version>
     <guava.version>30.1.1-jre</guava.version>
diff --git a/versions.txt b/versions.txt
index 62a01bba92..ccd2b6ac3e 100644
--- a/versions.txt
+++ b/versions.txt
@@ -1,4 +1,4 @@
 # Format:
 # module:released-version:current-version
 
-google-cloud-core:2.1.4:2.1.4
\ No newline at end of file
+google-cloud-core:2.1.5:2.1.5
\ No newline at end of file