of ambassadors and are inviolable and must not be entered by the host country except by permission of the head of the mission; likewise, the host country must never search the premises, may not seize its documents or property, and must protect the mission from intrusion or damage (Article 22). Article 30 extends this provision to the private residence of the diplomats. The archives and documents of a diplomatic mission are inviolable and shall not be seized or opened by the host government (Article 24). The host country must permit and protect free communication between the diplomats of the mission and their home country. A diplomatic bag must never be opened, even on suspicion of abuse, and a diplomatic courier must never be arrested or detained (Article 27). Diplomats must not be liable to any form of arrest or detention, and the receiving state must make all efforts to protect their person and dignity (Article 29). Diplomats are immune from the civil and criminal jurisdiction of the host state, with exceptions for professional activities outside the diplomat's official functions (Article 31). Article 32 permits sending states to waive this immunity. Diplomatic missions are exempt from taxes (Article 34) and customs duties (Article 36). Family members of diplomats living in the host country enjoy most of the same protections as the diplomats themselves (Article 37). Optional protocols The same year the treaty was adopted, two protocols were added as amendments; countries may ratify the main treaty without necessarily ratifying these optional agreements. Concerning acquisition of nationality. The head of the mission, the staff of the mission, and their families, shall not acquire the nationality of the receiving country. Concerning compulsory settlement of disputes. Disputes arising from the interpretation of this treaty may be brought before the International Court of Justice. Countries can choose to recognize their embassies as sovereign territory States parties to the convention , there are 193 state parties to the Vienna Convention, including all UN member states – with the exceptions of Palau and South Sudan – and the UN observer states of the Holy See and State of Palestine. The Republic of China signed and ratified the convention on 18 April 1961 and 19 December 1969, respectively, prior to the UN granting China's seat to the People's Republic of China. There are no states that have signed the treaty but not ratified it. See also Diplomatic immunity