Install the latest .NET Core SDK - not sure if .NET 8 is enough for old ASP.NET. Any way install both .NET 8 and .NET standard framework (.net 4.8.1). Install the latest .NET Core runtime(I guess .NET 8 installation takes care of it, anyway. If things dont work - install .NET runtime separately)

This software is important - I guess it is ASP.NET Core runtime.

Anyway, google --- ASP.NET Core runtime - Windows Hosting Bundle Installer -- whatever software suggestion comes in Google, pls install it.

Whenever you migrate to the latest version, Install the above software in Windows Server 2022

Of course, we need to install the latest IIS on the Windows server.

I will write a separate article about the IIS Migration

For IIS migration, list all software present in the old server. Install all this software on the new server. If you miss any software, there will be a code break/your apps will not work on the new server.

If you are using Excel Libraries on the old server, this may not be allowed on the new server. Use NPOI/EXcelDataReader opensource nugest package instead.
Below are the steps for IIS 10 Migration

First, we have to export all IIS settings from IIS 6 or IIS 8.

The settings will be exported/saved as a zip file.

You may get an error, or export settings may fail if you try to export all IIS settings.

So we have to export one set by one. Please follow the below steps.

In IIS 8/IIS 6/Old Server.

Right-click IIS => Export Server Package => Manage Components.

We have to export each item using the provider name dropdown.

Webserver and webserver60 are important.

Before exporting, delete unwanted files inside a physical directory because exporting some of the items in the dropdown may fail if the physical directory size is large.

After exporting, import each component's settings.

Right-click IIS => Import and import zip file settings in the same order they are exported.

Importing some components may fail, but move on to the next component.

Dont stop if you get errors while importing or exporting some of the components. Yes, you may not be able to export some of the settings, but dont worry. Move on to the next setting.

When you install IIS from Server Explorer, Imort Option may not be there when you right-click IIS.