The UPU only regulates the sending of letters and small parcels up to 2 kg. At the time of the first implementation of the agreement, most international mail was letters. Now that emails and apps like Snapchat and WhatsApp connect people around the world in real time, the number of letters has decreased. At the same time, e-commerce is increasing the number of small packages shipped internationally. The UPU, now an arm of the United Nations, was founded in 1874 by the Treaty of Bern. Prior to this agreement, cross-border mailing of letters was complex and often costly. Some countries had bilateral postal agreements, others did not. It was difficult to send a letter to someone in a country that did not have a mutual agreement with your country. You should rely on a redirect service. You might even have added stamps from any country through which your letter went. The Universal Postal Congress is the most important body of the UPU.
The main objective of the four-year congress is to examine proposals to amend the upU`s actions, including the UPU Constitution, general regulations, the convention and the postal services agreement. The Congress also serves as a forum for participating member countries to discuss a wide range of issues related to international postal services, such as market trends, regulation and other policy issues. The first UPU congress was held in Bern in 1874. Delegates from 22 countries attended. UPU conventions are held every four years and delegates often receive special philatelic albums produced by member countries for the period since the last Congress.  Why is it important? Without the UPU, postal operators would have to negotiate separate bilateral agreements with any other operator with whom they wished to exchange international mail. More importantly, without the UPU, countries would not be guaranteed a postal service to and from almost any other nation around the world. Delegates from about 140 countries cheered when Bishar Hussein, the head of the Universal Postal Union, said the new formula had been adopted. The day before, he had warned that a U.S. withdrawal could create chaos in the international postal service. Towards the end of the 19th century, the UPU adopted rules for stamp design to ensure maximum efficiency in the processing of international mailings. One rule provided that stamp values should be shown in numbers, as unit values written in letters were not comprehensible to all.
 Another required member countries to use the same colours on their stamps as those issued for postcards (green), normal letters (red) and international mail (blue), a system that has remained in service for several decades.  Under the agreement, the United States will also pay US$40 million to the Postal Union over a five-year period. The funding will help the postal union promote the use of computerized systems that provide security against shipping drugs such as fentanyl and other dangerous products, said David Dadge, a spokesman for the union. Companies like eBay have criticized the current system as unfair, but have warned that a U.S. withdrawal could have disastrous consequences, especially before the holiday season. The company had asked the United States to reach some kind of agreement and said on Wednesday that it supported the result. To integrate postal services and the Internet, the UPU .post was parising.   The UPU expects to unveil a whole new set of international digital postal services, including e-mail.