Configuring DITA Open Toolkit Version
In order to support DITA specialization and customization it is sometimes necessary to specify a specific version of the DITA Open Toolkit (OTK). In ePublisher, you can easily change which version of the OTK is used to preprocess all of your content on a project by project basis. You can even configure your stationery to use a specific version.
To change your project's OTK version
In your Stationery design project, on the Project menu, click Project Settings...
Expand the XML Input tab and locate the row labeled:
DITA Open Toolkit version.Choose from one of the available versions and then select the OK button.
Note: Usually, it is fine to just use the latest version, however, it may be necessary to use an older version if you have specializations or other customizations that have not yet been migrated.