The new entry form has been printed and being distributed. However, this does not mean old forma are invalid, as some have already experienced that officers at a passport control have no problem accepting old forms. Airlines are being told to hand out old forms till ran out of the stock then switch to new form. If you happen to have few old forms in your hand then there is no reason to get rid of old forms, you can still use them.

Sure, from ten years from now if you walk up to a passport control with an old form you may be asked to fill the new form, but at this moment you can still use an old form.