There are a few promotional offers each year, usually with 10 or 15% discount. They are never announced in advance. Subscribe to the newsletter to be informed once they start.

Aside: it as a fairly big issue: overcrowding last yr in summer. So one may/can expect they will be more stringent to not allow discounted passes valid anytime-only off-season. But that is only my impression, there s nothing certain by now

But you likely ask this for travel much later-well, even if there is NO offer, you can always buy pas the very last moment (and simply be a little more smart in booking and avoiding RES-do not follow all the sheep that all want to go very same way).

In the past I have even bought paper pass when waiting for a plane in Köln-Airportstation-for use after that flight to start.

"They” being NS and DB, on 5 ICEs leaving the Netherlands, so no need to scare people off in general.