The DITA Open Toolkit PDF transform, which was part of the 1.2.2 release, has been deprecated in favor of the PDF2 transform, which makes use of a plug-in from Idiom Technologies, Inc.
The PDF transform made use of FOP 0.20. By default, the PDF2 transform makes use of RenderX XEP.
For more information about the PDF2 transform, see Processing to PDF2 targets.