53In the present case, the Court finds that by adopting Annex X, the legislature sought to amend the system previously in force, in particular the system of paying a contribution in respect of accommodation. That amendment could not prejudice the rights acquired by the applicant. Article 27 of Annex X expressly provides that ‘an official or a member of the staff covered by Regulation No 3018/87 shall, for a period not exceeding the duration of the assignment being carried out when these provisions enter into force and for a maximum of five years, receive remuneration at least equal to that which he was receiving the day before entry into force of these provisions’.