Can you post the old and new versions of the /etc/cups/ppd/*.ppd files?
If you set the "Properties -> Installed Options -> Duplex (Option|Unit)" option to true again and also turn on duplexing by default, does duplexing work again?
Can you post the old and new versions of the /etc/cups/ppd/*.ppd files?
If you set the "Properties -> Installed Options -> Duplex (Option|Unit)" option to true again and also turn on duplexing by default, does duplexing work again?