Migrating from FOP 0.20 to 0.93

Having upgraded a FOP and Batik application to use Batik 1.6 seemed to break the Barcode4J plugin for FOP 0.20 prompting me to begin migration to FOP 0.93. This looks like a major task, requiring substantial modifications to the FO stylesheet base. http://xmlgraphics.apache.org/fop/compliance.html