diff --git a/benchmarks/RemoteBenchmark/Messages/Messages.csproj b/benchmarks/RemoteBenchmark/Messages/Messages.csproj
index 75dc4acc2f..68ceb95e79 100644
--- a/benchmarks/RemoteBenchmark/Messages/Messages.csproj
+++ b/benchmarks/RemoteBenchmark/Messages/Messages.csproj
@@ -3,7 +3,7 @@
     <TargetFrameworks>netstandard2.1;net5.0</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.14.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.6" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
     <PackageReference Include="Grpc.Tools" Version="2.36.0" PrivateAssets="All" />
   </ItemGroup>
diff --git a/examples/ClusterGrainHelloWorld/Messages/Messages.csproj b/examples/ClusterGrainHelloWorld/Messages/Messages.csproj
index 6a7555eb1a..48ae7235bd 100644
--- a/examples/ClusterGrainHelloWorld/Messages/Messages.csproj
+++ b/examples/ClusterGrainHelloWorld/Messages/Messages.csproj
@@ -6,7 +6,7 @@
     <LangVersion>preview</LangVersion>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.14.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.6" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
     <PackageReference Include="Grpc.Tools" Version="2.36.0" PrivateAssets="All" />
   </ItemGroup>
diff --git a/examples/Persistence/Messages/Messages.csproj b/examples/Persistence/Messages/Messages.csproj
index 87f5e6d76e..4a18789d39 100644
--- a/examples/Persistence/Messages/Messages.csproj
+++ b/examples/Persistence/Messages/Messages.csproj
@@ -3,7 +3,7 @@
     <TargetFramework>netstandard2.1</TargetFramework>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.14.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.6" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
     <PackageReference Include="Grpc.Tools" Version="2.36.0" PrivateAssets="All" />
   </ItemGroup>
diff --git a/src/Proto.Actor/Proto.Actor.csproj b/src/Proto.Actor/Proto.Actor.csproj
index 8de2d7f3f6..1054961b88 100644
--- a/src/Proto.Actor/Proto.Actor.csproj
+++ b/src/Proto.Actor/Proto.Actor.csproj
@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.14.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.6" />
     <PackageReference Include="Grpc.Tools" Version="2.36.0" PrivateAssets="All" />
     <PackageReference Include="IsExternalInit.System.Runtime.CompilerServices" Version="1.0.0" Condition="'$(TargetFramework)' == 'netstandard2.1'" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="5.0.1" />