diff --git a/engine/examples/dotnetcore.md b/engine/examples/dotnetcore.md
index 9e076d3428..725afb5238 100644
--- a/engine/examples/dotnetcore.md
+++ b/engine/examples/dotnetcore.md
@@ -42,7 +42,7 @@ tutorial](https://www.asp.net/get-started) to initialize a project or clone our
    the `Dockerfile` to use the DLL file of your project.
 
 ```dockerfile
-FROM mcr.microsoft.com/dotnet/core/sdk:2.2 AS build-env
+FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS build-env
 WORKDIR /app
 
 # Copy csproj and restore as distinct layers
@@ -54,7 +54,7 @@ COPY . ./
 RUN dotnet publish -c Release -o out
 
 # Build runtime image
-FROM mcr.microsoft.com/dotnet/core/aspnet:2.2
+FROM mcr.microsoft.com/dotnet/core/aspnet:3.1
 WORKDIR /app
 COPY --from=build-env /app/out .
 ENTRYPOINT ["dotnet", "aspnetapp.dll"]