title: How to issue warning/error when using older version of Doxygen?
body: <p>I'm planning to use doxygen to document a project. It's an OSS project whose current documentation is of questionable quality. The reason I've decided to go with doxygen is because from version 1.8, doxygen has added support for Markdown (text formatter; think we use it on this site too).</p>
  
  <p>A concern of mine is for the people who might end up using older versions of Doxygen (for example, it hasn't been updated in the current Ubuntu LTS release).</p>
  
  <p>Is it possible to add some setting or marking in the Doxyfile (doxygen configuration file), such that it will issue an error/warning if someone tries to generate the documentation using an older version of doxygen?</p>
  
  <p>(Ideally, explaining the cause of error as well)</p>