Error - File Download Handler Receive Content Length

[zzap64]

Any idea how to address this ?
Assets/PlayMaker Custom Actions/WWW/WebRequest.cs(397,27): warning CS0672: Member 'FileDownloadHandler.ReceiveContentLength(int)' overrides obsolete member 'DownloadHandler.ReceiveContentLength(int)'. Add the Obsolete attribute to 'FileDownloadHandler.ReceiveContentLength(int)'.