OpenImmo/src/main/java/org/openestate/io/openimmo/converters/OpenImmo_1_2_7.java
protected void downgradeBefeuerungElements(Document doc) throws JaxenException {
        List nodes = XmlUtils.newXPath(
                "/io:openimmo/io:anbieter/io:immobilie/io:ausstattung/io:befeuerung[@KOHLE or @HOLZ or @FLUESSIGGAS]",
                doc).selectNodes(doc);
        for (Object item : nodes) {
            Element node = (Element) item;
            node.removeAttribute("KOHLE");
            node.removeAttribute("HOLZ");
            node.removeAttribute("FLUESSIGGAS");
        }
    }
protected void downgradeBefeuerungElements(Document doc) throws JaxenException {
        List nodes = XmlUtils.newXPath(
                "/io:openimmo/io:anbieter/io:immobilie/io:ausstattung/io:befeuerung[@KOHLE or @HOLZ or @FLUESSIGGAS]",
                doc).selectNodes(doc);
        for (Object item : nodes) {
            Element node = (Element) item;
            node.removeAttribute("KOHLE");
            node.removeAttribute("HOLZ");
            node.removeAttribute("FLUESSIGGAS");
        }
    }
Downgrade &lt;befeuerung&gt; elements to OpenImmo 1.2.6.
<p>
The attributes "KOHLE", "HOLZ", "FLUESSIGGAS" of &lt;befeuerung&gt;
elements are not available in OpenImmo 1.2.6.

@param doc OpenImmo document in version 1.2.7
@throws JaxenException if xpath evaluation failed