Out the box InstantForum.NET 2010 currently targets the .NET 2.0 run-time and will work fine on .NET 2.0, .NET 3.5 & 3.5 SP1. We will be moving to .NET 4.0 out the box with future InstantForum.NET updates as more of our customers also move to .NET 4.0. To help customers looking to use the InstantForum.NET 2010 releases under .NET 4.0 you can find below two web.config files you can use which will ensure InstantForum.NET works correctly under the .NET 4.0 run-time Integrated .NET 4.0 Application Pools If your running InstantForum.NET under a IIS 7 Integrated ASP.NET 4.0 application pool please download the "IFNET2010_Integrated_DotNet4.0_WebConfig.zip" file attached below. This contains a web.config which will work fine for .NET 4.0 Integrated Application Pools. Classic .NET 4.0 Application Pools If your running InstantForum.NET within IIS6 or under a IIS 7 Classic ASP.NET 4.0 application pool please download the "IFNET2010_Classic_DotNet4.0_WebConfig.zip" file attached below. This contains a web.config which will work fine for .NET 4.0 Classic Application Pools. Each download contains a single web.config file which you should use if your running under .NET 4.0. Don't forget you'll need to update the database connection string within the web.config to point to your InstantForum.NET database. If you have any questions with regard to running our products under .NET 4.0 please don't hesitate to open a support ticket or contact us.