enscript duplex option works on F17 but not F20 or F21

[Robert Moskowitz]

These are the only versions of Fedora I have handy...

I use enscript to print IETF docs off in 2up/duplex:

enscript -2r --margins=:::45 -DDuplex:true -P HP8600 
draft-moskowitz-sse-00.txt

Worked fine last fall, then stopped working when I installed F20; I 
don't recall what I was running prior, I think F19.  What stopped was 
the Duplex feature.  I put up with this for the past year, no 2-sided 
printing.  So I tried it on the F21 beta today, and still no duplex.  
Then I remembered I have an Asus EE 4g Surf with F17 on it.  I set up 
the printer and this version DOES do duplex.

So some point, I think with F20 something changed, perhaps in hplip such 
that the Duplex option is no longer working.

Any ideas on how to figure this out?  Printing IETF docs nicely is not 
so easy.  They are exactly formated to page size, and you can't pay 
around with that so easily.  It took me a bit to figure out the margins 
to get it to fit.

Oh, Libre office, Firefox, and Thunderbird all do duplex printing just 
fine to the HP8600.  There is a nice dialog to select 2-sided printing.