#404handlers.config

    Configuration file for legacy NotFoundHandlers - to register custom code within the Umbraco incoming request pipeline, including the legacy way to handle a custom 404 error.

    The Default Handlers are listed in this configuration file for 'backwards compatibility':

    <NotFoundHandlers>
      <notFound assembly="umbraco" type="SearchForAlias" />
      <notFound assembly="umbraco" type="SearchForTemplate"/>
      <notFound assembly="umbraco" type="SearchForProfile"/>
      <notFound assembly="umbraco" type="handle404"/>
    </NotFoundHandlers>
    

    The concept of NotFoundHandlers has been replaced by IContentFinders - Implementing an IContentFinder

    Custom 404's are now handled within a custom IContentFinder by setting the Is404 property to true for the PublishedContentRequest processed by the IContentFinder or by registerring the IContentFinder as a ContentLastChanceFinder - Using an IContentFinder for Custom 404s

    If you upgrade from an older version of Umbraco then legacy NotFoundHandlers listed here 'should' still work - The request pipeline contains a ContentFinderByNotFoundHandlers IContentFinder that will attempt to execute the functionality of any legacy NotFoundHandlers, but it's recommended to move your custom request handling logic to IContentFinders.