Judgment of the Court (Fifth Chamber) of 6 October 2021.#Top System SA v État belge.#Request for a preliminary ruling from the Cour d'appel de Bruxelles.#Reference for a preliminary ruling – Copyright and related rights – Legal protection of computer programs – Directive 91/250/EEC – Article 5 – Exceptions to the restricted acts – Acts necessary to enable the lawful purchaser to correct errors – Concept – Article 6 – Decompilation – Conditions.#Case C-13/20.