Rome Statute of the International Criminal Court (c) The Deputy Prosecutors and staff of the Office of the Prosecutor may be waived by the Prosecutor; (d) The Deputy Registrar and staff of the Registry may be waived by the Registrar. Article 49 Salaries, allowances and expenses The judges, the Prosecutor, the Deputy Prosecutors, the Registrar and the Deputy Registrar shall receive such salaries, allowances and expenses as may be decided upon by the Assembly of States Parties. These salaries and allowances shall not be reduced during their terms of office. Article 50 Official and working languages 1. The official languages of the Court shall be Arabic, Chinese, English, French, Russian and Spanish. The judgements of the Court, as well as other decisions resolving fundamental issues before the Court, shall be published in the official languages. The Presidency shall, in accordance with the criteria established by the Rules of Procedure and Evidence, determine which decisions may be considered as resolving fundamental issues for the purposes of this paragraph. 2. The working languages of the Court shall be English and French. The Rules of Procedure and Evidence shall determine the cases in which other official languages may be used as working languages. 3. At the request of any party to a proceeding or a State allowed to intervene in a proceeding, the Court shall authorize a language other than English or French to be used by such a party or State, provided that the Court considers such authorization to be adequately justified. Article 51 Rules of Procedure and Evidence 1. The Rules of Procedure and Evidence shall enter into force upon adoption by a twothirds majority of the members of the Assembly of States Parties. 2. Amendments to the Rules of Procedure and Evidence may be proposed by: (a) Any State Party; (b) The judges acting by an absolute majority; or (c) The Prosecutor. Such amendments shall enter into force upon adoption by a two-thirds majority of the members of the Assembly of States Parties. 3. After the adoption of the Rules of Procedure and Evidence, in urgent cases where the Rules do not provide for a specific situation before the Court, the judges may, by a two-thirds majority, draw up provisional Rules to be applied until adopted, amended or rejected at the next ordinary or special session of the Assembly of States Parties. 4. The Rules of Procedure and Evidence, amendments thereto and any provisional Rule shall be consistent with this Statute. Amendments to the Rules of Procedure and Evidence as well as provisional Rules shall not be applied retroactively to the detriment of the person who is being investigated or prosecuted or who has been convicted. 31