This October, the IMU Executive Committee endorsed the proposal made by the Commission for Developing Countries (CDC) regarding the definition of Developing Countries to be used by IMU during the next 4-year period. The list consists of all the countries classified by the World Bank (WB) in the categories: Low income (<USD 1.025), Lower middle income (USD 1.026 – 3.995), and Upper middle income (USD 3.996 – 12.375) in accordance with the WB Database by July 2019. These are all countries with Gross National Income (GNI) per capita in USD, not exceeding USD 12.375, with the WB data of 2018. See
https://data.worldbank.org/indicator/NY.GNP.PCAP.CD

As in the previous term, the following subdivision in priority groups has been established, for different purposes:

Priority 1 (WB Low income) - GNI per capita in USD below 1.025
Priority 2 (WB Lower middle income) - GNI per capita in USD 1.026 – 3.995
Priority 3 (WB Upper middle income, A) - GNI per capita in USD 3.996 – 6.785
Priority 4 (WB Upper middle income, B) - GNI per capita in USD 6.786 – 9.575
Priority 5 (WB Upper middle income, C) - GNI per capita in USD 9.576 – 12.375

The list of Developing Countries with indication of their priority classification can be found in https://www.mathunion.org/cdc/about-cdc/definition-developing-countries

At any moment, IMU member countries can ask the IMU to consider inclusion/exclusion as a Developing Country. The application should be motivated and, on the basis of the evidences presented by the country, CDC would make a recommendation to EC for a case-by-case decision. If a country's World Bank status as a Developing Country has changed between the data used to decide on developing countries and the time of the request, this information should be included as part of the evidence.