[NTG-context] is it possible to produce PDF with version < 1.3

hello all the pdf I've produced declares to be PDF v1.5 which seems to be unreadable if the acrobat version is not 8 Is it possible to demand an older version of PDF for the result of a compilation with texexec or does it depend on the ConTeXt features used? As always, any hint would be greatly appreciated. -- Yvon Henel