[oXygen-user] DTD validation and namespace prefixes

[Lars Huttar]

Hello,
I have a Schematron schema that formerly was validating successfully 
against a DTD, but now with Oxygen 8.2, is failing validation.
The Schematron schema begins

    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE sch:schema SYSTEM "schematron.dtd">
    <sch:schema xmlns:sch="http://www.ascc.net/xml/schematron"
    defaultPhase="done">

The DTD, schematron.dtd, begins

    <!ELEMENT schema  ( title?, ns*, phase*, p*, pattern+ , p*,
    diagnostics )>

As you can see, the DTD does not allow for the sch: namespace prefix on 
the <schema> element.
Yet the validation used to be successful.
Was the old behavior incorrect?

Maybe I should just stop using schematron.dtd and use the 
Schematron-validator that Oxygen provides?

Lars