diff --git a/samples/frontend-backend/backend/backend.csproj b/samples/frontend-backend/backend/backend.csproj
index 4e98f5a2..7271366f 100644
--- a/samples/frontend-backend/backend/backend.csproj
+++ b/samples/frontend-backend/backend/backend.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net5.0</TargetFramework>
     <RootNamespace>Backend</RootNamespace>
   </PropertyGroup>
 
diff --git a/samples/frontend-backend/frontend/frontend.csproj b/samples/frontend-backend/frontend/frontend.csproj
index 0aa4abc0..26249ad7 100644
--- a/samples/frontend-backend/frontend/frontend.csproj
+++ b/samples/frontend-backend/frontend/frontend.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net5.0</TargetFramework>
     <RootNamespace>Frontend</RootNamespace>
   </PropertyGroup>
 
diff --git a/src/Microsoft.Tye.Core/DockerfileGenerator.cs b/src/Microsoft.Tye.Core/DockerfileGenerator.cs
index e4503ff7..68d19d44 100644
--- a/src/Microsoft.Tye.Core/DockerfileGenerator.cs
+++ b/src/Microsoft.Tye.Core/DockerfileGenerator.cs
@@ -101,7 +101,7 @@ namespace Microsoft.Tye
                 container.BaseImageName = "mcr.microsoft.com/dotnet/core/runtime";
             }
 
-            if (string.IsNullOrEmpty(container.BaseImageTag) && project.TargetFrameworkName == "netcoreapp")
+            if (string.IsNullOrEmpty(container.BaseImageTag) && (project.TargetFrameworkName == "netcoreapp" || project.TargetFrameworkName == "net"))
             {
                 container.BaseImageTag = project.TargetFrameworkVersion;
             }
@@ -112,7 +112,7 @@ namespace Microsoft.Tye
             }
 
             container.BuildImageName ??= "mcr.microsoft.com/dotnet/core/sdk";
-            container.BuildImageTag ??= "3.1";
+            container.BuildImageTag ??= project.TargetFrameworkVersion;
 
             if (container.ImageName == null && application.Registry?.Hostname == null)
             {