What is the difference between ASPNetCoreModule and ASPNetCoreModuleV2?

• ASPNetCoreModule ("version 1") is the IIS Module that enables IIS to run ASP.NET Core 1.x and 2.x applications when they're running in .NET Core

  • ASP.NET Core 1.x and 2.x (but not ASP.NET Core 3.x and later) can alternatively run on top of .NET Framework, instead of .NET Core, in which case you can use IIS' built-in CLR pipeline without the need for ASPNetCoreModule.
  • Version 1 was discontinued and removed from the ASP.NET GitHub repo in January 2019. The only reason you would be using V1 today is if you're still running an ASP.NET Core 1.x application.
    • Which you should not be doing anyway.

• ASPNetCoreModuleV2 supports ASP.NET Core 2.0 and later (including ASP.NET Core 3.x, .NET 5, .NET 6, etc). It also supports more features than V1 (such as custom offline messages).

when to use each of them in which scenario.

Here's a flowchart:

• Are you looking to run your ASP.NET Core application in IIS (without running on the .NET Framework)?
  • Yes:
    • Are you targeting ASP.NET Core 1.x?
      • Yes _{(you masochist)}
        • Use ASPNetCoreModule (V1) and update to ASP.NET Core 3.1 LTSB pronto.
      • No
        • Use ASPNetCoreModuleV2
    • Are you targeting ASP.NET Core 2.x, ASP.NET Core 3.x, .NET 5 or .NET 6?
      • Yes
        • Use ASPNetCoreModuleV2
      • No
        • Then this entire StackOverflow question is irrelevant to you
  • No
    • You don't need ASPNetCoreModule nor ASPNetCoreModuleV2

In short: there is no reason to be using ASPNetCoreModule ("V1") today.