.NET中没有WebserverRequest。这必须是第三方代码或您自己的代码。我猜想EnergyUsageManager。此第三方代码需要.NET 4.6+。因此，您无法将代码降级到之前的版本。它不受支持。

There is no WebserverRequest in .NET. This has to be third party code or your own. I'm guessing EnergyUsageManager. This third party code requires .NET 4.6+. Therefore you cannot downgrade your code to a version before that. It isn't supported.

没有解决方法。您需要将代码保持在4.6+以上，或者将此库的使用替换为在早期版本上运行的内容。

There is no workaround. You either need to keep your code at 4.6+ or replace your usage of this library with something that runs on an earlier version.