(b) an exclusive licence has been granted in respect of a patent; no damages for the infringement of the patent shall be recoverable by the new owner or the exclusive licensee, as the case may be, in respect of any infringement of that patent during the period from the date of the change of ownership or grant of exclusive licence, as the case may be, until the registration in terms of section fiftythree of that change of ownership or grant of exclusive licence, as the case may be, unless such registration was effected within six months of the change of ownership or grant of exclusive licence. (2) If proceedings are taken in respect of infringement of a patent committed after the failure to pay any fee within the prescribed time and before any extension of time for such payment, the High Court may, if it thinks fit, refuse to award any damages in respect of such infringement. 51 Remedy for groundless threats of infringement proceedings (1) Where any person, whether entitled to or interested in a patent or an application for a patent or not, by circulars, advertisements or otherwise threatens any other person with proceedings for infringement of a patent, any person aggrieved thereby may bring an action against him in the High Court in accordance with the rules of that court for any such relief as is mentioned in subsection (2). [amended by Act 9 of 2002, with effect from the 20th December, 2002.] (2) Unless, in any action brought in terms of subsection (1), the defendant proves that the acts in respect of which proceedings were threatened constitute or, if done, would constitute, an infringement of a patent or of rights arising from the publication of a complete specification in respect of a claim of the specification not shown by the plaintiff to be invalid, the plaintiff shall be entitled to the following relief, that is to say— (a) a declaration to the effect that the threats are unjustifiable; (b) an interdict against the continuance of the threats; (c) such damages, if any, as he has sustained thereby. (3) For the avoidance of doubt, it is hereby declared that a mere notification of the existence of a patent shall not constitute a threat of proceedings within the meaning of subsection (1). (4) The defendant in any action brought in terms of subsection (1) may apply, by way of counter-claim in the action, for any relief to which he would be entitled in a separate action in respect of any infringement by the plaintiff of the patent to which the threats relate. 52 Power of High Court to make declaration as to non-infringement (1) A declaration that the use by any person of any process or the making or use or sale by any person of any article does not or would not constitute an infringement of a claim of a patent may be made by the High Court in proceedings between that person and the patentee or the holder of an exclusive licence under the patent, notwithstanding that no assertion to the contrary has been made by the patentee or licensee, if it is shown that— (a) the plaintiff has applied in writing to the patentee or licensee for a written acknowledgement to the effect of the declaration claimed and has furnished him with full particulars in writing of the process or article in question; and (b) the patentee or licensee has refused or neglected to give such an acknowledgement. (2) In proceedings for a declaration brought by virtue of this section the High Court shall make such order in respect of the costs of all parties to the proceedings as it deems fit: Provided that a patentee or holder of an exclusive licence under the patent shall not be liable for any costs unless he enters an appearance and takes part in the proceedings. (3) The validity of a claim of the specification of a patent shall not be called in question in proceedings for a declaration brought by virtue of this section, and accordingly the making or refusal of such a declaration in the case of a patent shall