diff --git a/ClosedXML/ClosedXML.csproj b/ClosedXML/ClosedXML.csproj
index b9e5568..303a76b 100644
--- a/ClosedXML/ClosedXML.csproj
+++ b/ClosedXML/ClosedXML.csproj
@@ -25,8 +25,9 @@
     <OutputPath>bin\Release.Signed\</OutputPath>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <SignAssembly>true</SignAssembly>
+    <Optimize>true</Optimize>
     <AssemblyOriginatorKeyFile>ClosedXML.snk</AssemblyOriginatorKeyFile>
-    <DefineConstants>$(DefineConstants);STRONGNAME</DefineConstants>
+    <DefineConstants>$(DefineConstants);RELEASE;STRONGNAME</DefineConstants>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)'=='Release'">
diff --git a/ClosedXML_Tests/ClosedXML_Tests.csproj b/ClosedXML_Tests/ClosedXML_Tests.csproj
index 7ad6697..a912f8a 100644
--- a/ClosedXML_Tests/ClosedXML_Tests.csproj
+++ b/ClosedXML_Tests/ClosedXML_Tests.csproj
@@ -16,8 +16,9 @@
   <PropertyGroup Condition="'$(Configuration)'=='Release.Signed'">
     <OutputPath>bin\Release.Signed\</OutputPath>
     <SignAssembly>true</SignAssembly>
+    <Optimize>true</Optimize>
     <AssemblyOriginatorKeyFile>ClosedXML.snk</AssemblyOriginatorKeyFile>
-    <DefineConstants>$(DefineConstants);STRONGNAME</DefineConstants>
+    <DefineConstants>$(DefineConstants);RELEASE;STRONGNAME</DefineConstants>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(TargetFramework)' == 'netcoreapp2.0' ">