Upgrade .Net 5 to .Net 6

This is a quick check list that you can follow to update your application from .Net 5 to .Net 6

You can watch a full video on how to do this on a full WebApi application on Youtube

1- Upgrade the reference in csproj files

// Old
<PropertyGroup>
   <TargetFramework>net5.0</TargetFramework>
</PropertyGroup>

// New
<PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
</PropertyGroup>

2- Upgrade the packages

// Old
<ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="5.0.11" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.UI" Version="5.0.11" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc.Versioning" Version="5.0.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="5.0.11">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <PackageReference Include="Swashbuckle.AspNetCore" Version="5.6.3" />
 </ItemGroup>

// New
<ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="6.0.0" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.UI" Version="6.0.0" />
    <PackageReference Include="Microsoft.AspNetCore.Mvc.Versioning" Version="5.0.0" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="6.0.0">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.2.3" />
</ItemGroup>

3- Upgrade the namespaces

// Old
namespace CoolApplication
{
    public class User
    {
        public int Id { get; set; }

        public string FirstName { get; set; }

        public string LastName { get; set; }

        public string Email { get; set; }
  }
}

// New
namespace CoolApplication;

public class User
{
    public int Id { get; set; }

    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string Email { get; set; }
}

4- Migrate your startup class to Program.cs

.Net 5 Startup Class

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace CoolApplication
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapRazorPages();
            });
        }
    }
}

.Net 5 Program.cs

using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;

namespace CoolApplication
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>();
                });
    }
}

To .Net 6 Program.cs which contains everything

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddRazorPages();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error");
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();

app.UseAuthorization();

app.MapRazorPages();

app.Run();

To view the full list of upgrade option check Microsoft documentation on the link below:
https://docs.microsoft.com/en-us/aspnet/core/migration/50-to-60?view=aspnetcore-6.0&tabs=visual-studio-code

Comments

[Andreas Jakof]

I just like to mention, that you CAN change the source files, but you don‘t need to.
The old style with namespaces, classes and Startup.cs is still valid.

So in order to migrate to .Net 6 all you need to do, is changing the target framework. C#10 syntax is optional.