Draft Article 4, which was amended to provide that, where the respondent included, in its response to the notice of arbitration, claims against a party other than the claimant, its response would include a notice of arbitration in respect of that third party. Draft Article 17(5) introduces a provision enabling the tribunal to join a party to the arbitration, provided they are a party to the arbitration agreement. However, such joinder could only occur after the tribunal had been constituted. The amendment to draft Article 4 means that a respondent could, in its response to the notice of arbitration, formulate a claim against a party other than the claimant, rather than waiting until formal joinder at a later stage. This also allows the respondent to avoid having to serve a separate notice of arbitration.

Draft Article 26 (interim measures), which was amended to provide that a party requesting an interim measure may be liable for any costs and damages caused by the measure to any party if the tribunal later decides, based on the circumstances at that time, that the measure should not have been granted.