Any given debian release may contain one xerces-c package for each
major version of xerces-c.  It is expected that most releases will
have only a single version of xerces-c since major releases are rare.

The package "libxerces-c-dev" is always the development package for
the latest major version.  You may also use libxerces-cn-dev, where n
is the major version, to get the development package for the specific
major version.  For example, libxerces-c3-dev would be the development
packages for the latest 3.x release, and libxerces-c2-dev would be the
development packages for the latest 2.x release.

If your package uses on xerces-c, you should generally declare a build
dependency on libxerces-c-dev.  You should only use a specific version
of the dev package if it is specifically known that your package will
not work (yet) with a new version of xerces-c when it comes out.

 -- Jay Berkenbilt <qjb@debian.org>, Sat, 22 Mar 2008 13:58:45 -0400