coder.xml does not conform to DTD which it contains itself.

[epi]

Default coder.xml file in 6.6.9-3-Q16 windows installation does not conform to DTD which it contains itself. There's a <!ELEMENT codermap (coder)+> declaration, which states that at least one "coder" element is required inside "codermap" element. However, there's no coders (besides three commented ones), so the document is not valid. This causes problems with XmlConfig in WiX - the installer is not able to update coder.xml file with new formats supported by my coder, because coder.xml does not pass validation.
I suggest changing the above mentioned declaration to <!ELEMENT codermap (coder)*> (asterisk instead of a plus) to fix this problem.

[magick]

We'll get a patch to fix the problem you reported in the next point release of ImageMagick. Thanks.