File is derived from Import[file,"XML"]

The standard is double quote ("). Downstream programs reject the file. Is there an option that will change this behavior?

All input strings have double quotes, all output strings have single quotes.

Odd that even the on-screen display (copied to text) shows double quotes, e.g. XMLElement["Id", {}, {"2014-07-25T02:22:57.000Z"}

(Mathematica 10)

FOUND THE DOCUMENTATION under XML/tutorial/ExportingXML
The option is literally quoted. And there's a backslash you don't see.

Export[outfile, newxml, "XML" , "AttributeQuoting" -> "\""];