anchor.diff:  }
   ----
   
  -=== Build Dependency
  +=== As Build Dependency
   
   The last option is to move the `extension` project into Gradle's `buildSrc` directory. There are no additional dependencies
   to be defined on the consuming projects, as the extension will be automatically picked up by the `asciidoctor` task,
   as the compiled extension is already in the task's classpath.
  +
  +[appendix]
  +== Compatibility With Previous Releases
  +
  +=== Task Properties
  +
  +The following properties have been marked as deprecated. Developers are encouraged to migrate ASAP to the alternate
  +properties.
  +
  +[horizontal]
  +sourceDocumentNames:: an override to process multiple source files, which are relative to `sourceDir`.
  +  Use `sources { include 'name' }` instead.
  +sourceDocumentName:: an override to process a single source file. Use `sources { include 'name' }` instead.
  +backend:: the backend to use. Use `backends` instead.
  +
  +=== Behavior
  +
  +* The default value for `sourceDir` has changed from `src/asciidoc` to `src/docs/asciidoc`.
  +* Files specified in `sourceDocumentNames` must be relative to `sourceDir` and fully contained in `sourceDir`, in other words,
  +it's no longer possible to process documents placed outside of the project's sources. Attempts will be made to convert absolute paths
  +to relative paths  but conversion will not be guaranteed. Do not pass FileCollections as they will not convert correctly.
  +* Source files that are not reachable from `sourceDir`, will no longer cause a build exception, they will just be silently ignored.
  +* For backwards compatibility with older version, embedding `attributes` within `options` are still allowed, including legacy forms.
  +* Non-source files are no longer automatically copied, unless they are in the `images` folder and `resources` was never
  +called.
  +* Each backend will now write to a separate subfolder under `outputDir`. To have the old behaviour use
  +`separateOutputDirs = false`.
  +
  +=== Options & Attributes
  +
  +[source,groovy]
  +.build.gradle
  +----
  +// Map notation
  +attributes: toc: 'right',
  +            'source-highlighter': 'coderay',
  +            'toc-title': 'Table of Contents'
  +
  +// List notation
  +attributes: [
  +    'toc=right',
  +    'source-highlighter=coderay',
  +    'toc-title=Table of Contents'
  +]
  +
  +// String notation
  +attributes: 'toc=right source-highlighter=coderay toc-title=Table\\ of\\ Contents'
  +----
  +
  +IMPORTANT: Do not forget to transform Groovy strings into Strings (by explicitly invoking `.toString()` on them) when
  +used as option values, otherwise the Ruby runtime will throw an exception.
  +
  +Notice how spaces are escaped in the last key/value pair.
  
positive.code: The `extension` project is a sibling for `core`. The build file for the latter looks like this:
  
  [source,groovy]
  [subs="attributes,specialcharacters"]
  .build.gradle
  ----
  buildscript {
  
negative.code: }
  ----
  
  Files will be copied to below `+${outputDir}/${backend}+` (or just `+${outputDir}+` if `separateOutputDirs=false`)
  
  Unlike `sourceDir` files can be copied from anywhere in the filesystem.
  
  