Just updated by PTC:
“July 1, 2015: FOSI Retirement Notice
Beginning July 1, 2015, PTC will change the level of support for the FOSI composition engine from Standard to Sustained.
This includes the use of XSL-FO, the FOSI Editor and the Arbortext line numbering application.
Customers with an active Global Support agreement may continue to contact PTC Technical Support as well as have continued access to technical support web tools, the knowledgebase and prior maintenance releases.
However, there will be no additional maintenance releases or patches related to the FOSI composition engine.
The FOSI composition engine will continue to be included in the Arbortext suite of products, and customers may continue to use existing FOSI stylesheets.”