XML defines a set of "restricted characters" that cannot be used, even not encoded.
In 1.0, these restricted characters contain all control chars < 0x0020, except 0x0009, 0x000A and 0x000D.
In XML 1.1 only 0x0000 is restricted.
The org.alfresco.repo.exporter.ExporterComponent currently uses the org.dom4j.io.XMLWriter that only writes XML 1.0 and does not care about restricted characters.
- Upgrade to XML 1.1 for ACP files, and
- Use Woodstox FasterXML for the generation of XML files. It can be configured with an InvalidCharacterhandler that should be used to replace 0x0000 by either 0xFFFD (replacement char) or '_'.
I am not sure if the Exporter is part of "Infrastructure" or "Content Services".