Before 10 July 1964, states became members of the UPU by ratifying the latest version of the Treaty of Bern. After this date, states become members by ratifying the Constitution of the Universal Postal Union, which incorporated the Treaty of Bern and added provisions to it. Three states which were party to the Treaty of Bern in 1964, and hence members of the UPU, and which have signed but never ratified the Constitution are the Dominican Republic, Honduras, and Sudan.[2] These states are deemed to have "tacitly ratified" the agreement due to their continued participation in the UPU.[3] Also included as members are two "joint memberships" for dependent territories (one for the British overseas territories and one for the Caribbean constituent countries (Dutch: landen) of the Kingdom of the Netherlands (Aruba, Curaçao and Sint Maarten), originally as Netherlands Antilles). Dependent territories are not permitted to ratify the UPU Constitution, but because the Treaty of Bern allowed for dependencies to join the UPU,[3] listing these members separately as "Colonies, Protectorates, etc.",[4] the Constitution of the Universal Postal Union grandfathered them when membership was restricted to sovereign states.[3][5] However, neither the British nor the Dutch entities ratified the Treaty of Bern separate from the ratifications of the United Kingdom and the Kingdom of the Netherlands, respectively.
By virtue of article 23 of the UPU Constitution, other dependencies of UPU member states are covered by its membership. Territories covered by a sovereign member state are listed under that country.
Palestine – Has special observer status to the UPU since 1999, West Bank mail delivered through Jordan since 2008.[15][16] From [when?] up to 2010 Gaza strip mail was delivered through Israel.[17] On 15 November 2018, the president of the State of Palestine signed documents to accede to the UPU as a full member.[18] However, UPU member states did not approve the application.[19]
In the course of history a number of member countries of the UPU saw their membership lapse, due to political changes. Where there was an immediate successor state, membership would normally devolve on that state. In other cases membership lapsed.
^ abcState which became a UPU member by ratifying the Treaty of Bern and which signed the Constitution, but which has not ratified it.[2] These states are deemed to have "tacitly ratified" the agreement due to their continued participation in the UPU.[3]
^On 17 October 2018 the United States notified the UPU of its intention to withdraw from the union, which as per terms of the UPU constitution would become effective after one year.[11][12] However, the country indicated that it would be willing to remain a member if treaty arrangements which it finds problematic (the low terminal dues charged to developing countries to ship mail to developed countries) could be renegotiated during the course of the withdrawal period.[13] In October 2019, following an Extraordinary Congress of the UPU which agreed to increase terminal dues, the United States opted to remain a member of the UPU.[14]
^The Orange Free State acceded to the Postal Convention of Vienna in 1898, and a year later also acceded to that of Washington.[27] The state was dissolved at the signing of the Treaty of Vereeniging. Membership did not lapse but was absorbed into the British South African membership.
^The South African Republic was a member from 1895[28] until its dissolution at the signing of the Treaty of Vereeniging. Membership did not lapse but was absorbed into the British South African membership.
^Chen, Lung-chu (陳隆志) (8 October 2008). 萬國郵政聯盟與世界郵政日 [Universal Postal Union and World Post Day]. Taiwan New Century Culture and Education Foundation. Archived from the original on 16 October 2014.
^"UPU Period". Post Office in Paradise. Retrieved 3 February 2019.
List of member countries of the Universal Postal Union: showing their contribution class, geographical group and legal situation with regard to the Acts of the Union. Bern: International Bureau of the Universal Postal Union, 2005 13p.