The version information may be found on the Version tab. The version number is coded in the name of the library. The Xerces family of products also has a Java version. Xerces-C comes with no formal support. Every volunteer project obtains its strength from the people involved in it.
Mailing lists provide a simple and effective communication mechanism.
You can choose to lurk, or to actively participate. It's up to you. See Bug Reporting . I have a patch to the Xerces-C source code. Mail it to the Xerces-C mailing list at Apache.