diff --git a/Shadowsocks.Protobuf/Shadowsocks.Protobuf.csproj b/Shadowsocks.Protobuf/Shadowsocks.Protobuf.csproj
index af162ea3..ebc37940 100644
--- a/Shadowsocks.Protobuf/Shadowsocks.Protobuf.csproj
+++ b/Shadowsocks.Protobuf/Shadowsocks.Protobuf.csproj
@@ -5,7 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Google.Protobuf" Version="3.14.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
   </ItemGroup>
 
 </Project>
diff --git a/shadowsocks-csharp/packages.config b/shadowsocks-csharp/packages.config
index 2a489f8e..e4aeacf6 100644
--- a/shadowsocks-csharp/packages.config
+++ b/shadowsocks-csharp/packages.config
@@ -6,7 +6,7 @@
   <package id="Costura.Fody" version="3.3.3" targetFramework="net472" />
   <package id="Fody" version="4.2.1" targetFramework="net472" developmentDependency="true" />
   <package id="GlobalHotKey" version="1.1.0" targetFramework="net472" />
-  <package id="Google.Protobuf" version="3.11.4" targetFramework="net472" />
+  <package id="Google.Protobuf" version="3.15.0" targetFramework="net472" />
   <package id="NaCl.Core" version="1.2.0" targetFramework="net472" />
   <package id="Newtonsoft.Json" version="12.0.2" targetFramework="net472" />
   <package id="NLog" version="4.6.8" targetFramework="net472" />
diff --git a/shadowsocks-csharp/shadowsocks-csharp.csproj b/shadowsocks-csharp/shadowsocks-csharp.csproj
index 53ba14ee..492cbea8 100644
--- a/shadowsocks-csharp/shadowsocks-csharp.csproj
+++ b/shadowsocks-csharp/shadowsocks-csharp.csproj
@@ -36,7 +36,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="GlobalHotKeyCore" Version="1.2.0" />
-    <PackageReference Include="Google.Protobuf" Version="3.13.0" />
+    <PackageReference Include="Google.Protobuf" Version="3.15.0" />
     <PackageReference Include="MdXaml" Version="1.6.0" />
     <PackageReference Include="Microsoft.VisualBasic" Version="10.3.0" />
     <PackageReference Include="NaCl.Core" Version="1.2.0" />