In a decision of June 9, 2015 (X ZR 51/13 „Einspritzventil“), the German Federal Supreme Court had to deal with belated defense arguments and means for attack. Hereto, the German Federal Supreme Court has decided that defense arguments or means for attack or a change of the action or the defense of a patent claim in a limited version, which have not been refused on the basis of Article 83, para. 4, German Patent Act, which means after expiry of a given time-limit and consequently belated, cannot be rejected in appeal proceedings. Even if the German Federal Patent Court as the first instance did not decide whether a belatedly introduced invalidity argument is admissible or not, but nevertheless has decided on it to the merits, then this decision is subject matter of the appeal proceeding and has to be decided to the merits, too.