Adding version requirements for HttpResultAttribute

Author: mattchenderson

articles/azure-functions/dotnet-isolated-process-guide.md

@@ -346,7 +346,7 @@ public class MultipleOutputBindings
 }
 ```
 
-When using custom return types for multiple output bindings with ASP.NET Core integration, you must add the `[HttpResult]` attribute to the property that provides the result.
+When using custom return types for multiple output bindings with ASP.NET Core integration, you must add the `[HttpResult]` attribute to the property that provides the result. The `HttpResult` attribute is available when using [SDK 1.17.3-preview2 or later](https://www.nuget.org/packages/Microsoft.Azure.Functions.Worker.Sdk/1.17.3-preview2) along with [version 3.2.0 or later of the HTTP extension](https://www.nuget.org/packages/Microsoft.Azure.Functions.Worker.Extensions.Http/3.2.0) and [version 1.3.0 or later of the ASP.NET Core extension](https://www.nuget.org/packages/Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore/1.3.0).
 
 ### SDK types