Article 17 of the Convention of 27 September 1968 on Jurisdiction and the Enforcement of Judgments in Civil and Commercial Matters must be interpreted as meaning that where a written agreement containing a jurisdiction clause and stipulating that an agreement can be renewed only in writing has expired but has continued to serve as the legal basis for the contractual relations between the parties, the jurisdiction clause satisfies the formal requirements in Article 17 if, under the law applicable, the parties could validly renew the original agreement otherwise than in writing, or if, conversely, one of the parties has confirmed in writing either the jurisdiction clause or the set of terms which has been tacitly renewed and of which the jurisdiction clause forms part, without any objection from the other party to whom such confirmation has been notified.