diff --git a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Application/Fitnet.Contracts.Application.csproj b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Application/Fitnet.Contracts.Application.csproj
index ec37ef9a..fc5f83a9 100644
--- a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Application/Fitnet.Contracts.Application.csproj
+++ b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Application/Fitnet.Contracts.Application.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <ItemGroup>
-    <PackageReference Include="evolutionaryarchitecture.fitnet.common.api" Version="1.2.1" />
+    <PackageReference Include="evolutionaryarchitecture.fitnet.common.api" Version="4.1.0" />
     <PackageReference Include="evolutionaryarchitecture.fitnet.contracts.integrationevents" Version="1.0.7" />
     <PackageReference Include="JetBrains.Annotations" Version="2023.3.0" />
     <PackageReference Include="MassTransit.Abstractions" Version="8.1.3" />
diff --git a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Core.UnitTests/Fitnet.Contracts.Core.UnitTests.csproj b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Core.UnitTests/Fitnet.Contracts.Core.UnitTests.csproj
index 785aed39..42c63463 100644
--- a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Core.UnitTests/Fitnet.Contracts.Core.UnitTests.csproj
+++ b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Core.UnitTests/Fitnet.Contracts.Core.UnitTests.csproj
@@ -6,7 +6,7 @@
 
     <ItemGroup>
         <PackageReference Include="Bogus" Version="35.4.1" />
-        <PackageReference Include="EvolutionaryArchitecture.Fitnet.Common.Core" Version="1.2.1" />
+        <PackageReference Include="EvolutionaryArchitecture.Fitnet.Common.Core" Version="4.1.0" />
         <PackageReference Include="FluentAssertions" Version="6.12.0" />
         <PackageReference Include="xunit" Version="2.7.0" />
         <PackageReference Include="xunit.analyzers" Version="1.11.0" />
diff --git a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Core/Fitnet.Contracts.Core.csproj b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Core/Fitnet.Contracts.Core.csproj
index 9f2cdc75..d39fbc12 100644
--- a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Core/Fitnet.Contracts.Core.csproj
+++ b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.Core/Fitnet.Contracts.Core.csproj
@@ -5,7 +5,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="EvolutionaryArchitecture.Fitnet.Common.Core" Version="1.2.1" />
+    <PackageReference Include="EvolutionaryArchitecture.Fitnet.Common.Core" Version="4.1.0" />
     <PackageReference Include="EvolutionaryArchitecture.Fitnet.DomainDrivenDesign.BuildingBlocks" Version="1.2.1" />
   </ItemGroup>
   
diff --git a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.IntegrationEvents/Fitnet.Contracts.IntegrationEvents.csproj b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.IntegrationEvents/Fitnet.Contracts.IntegrationEvents.csproj
index 385f08ec..f8b24f27 100644
--- a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.IntegrationEvents/Fitnet.Contracts.IntegrationEvents.csproj
+++ b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.IntegrationEvents/Fitnet.Contracts.IntegrationEvents.csproj
@@ -4,6 +4,6 @@
     <Version>1.0.7</Version>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="EvolutionaryArchitecture.Fitnet.Common.Infrastructure" Version="1.2.1" />
+    <PackageReference Include="EvolutionaryArchitecture.Fitnet.Common.Infrastructure" Version="4.1.0" />
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.IntegrationTests/Fitnet.Contracts.IntegrationTests.csproj b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.IntegrationTests/Fitnet.Contracts.IntegrationTests.csproj
index 144a82f3..ad2611cf 100644
--- a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.IntegrationTests/Fitnet.Contracts.IntegrationTests.csproj
+++ b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts.IntegrationTests/Fitnet.Contracts.IntegrationTests.csproj
@@ -5,8 +5,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="evolutionaryarchitecture.fitnet.common.api" Version="1.2.1" />
-    <PackageReference Include="evolutionaryarchitecture.fitnet.common.integrationteststoolbox" Version="1.2.1" />
+    <PackageReference Include="evolutionaryarchitecture.fitnet.common.api" Version="4.1.0" />
+    <PackageReference Include="evolutionaryarchitecture.fitnet.common.integrationteststoolbox" Version="4.1.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.9.0" />
   </ItemGroup>
 
diff --git a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts/Fitnet.Contracts.csproj b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts/Fitnet.Contracts.csproj
index 40b80873..c86f7331 100644
--- a/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts/Fitnet.Contracts.csproj
+++ b/Chapter-4-applying-tactical-domain-driven-design/Fitnet.Contracts/Src/Fitnet.Contracts/Fitnet.Contracts.csproj
@@ -5,7 +5,7 @@
     </PropertyGroup>
     
     <ItemGroup>
-        <PackageReference Include="EvolutionaryArchitecture.Fitnet.Common.Api" Version="1.2.1" />
+        <PackageReference Include="EvolutionaryArchitecture.Fitnet.Common.Api" Version="4.1.0" />
         <PackageReference Include="JetBrains.Annotations" Version="2023.3.0" />
         <PackageReference Include="Swashbuckle.AspNetCore" Version="6.5.0" />
     </ItemGroup>