Invitations have been sent the following categories entitled to participate (ref. CV/Art. 23): 
- Member States [CV/268]
 - Palestine [Res. 99 (Rev. Busan, 2014)]
 - Observers which participate in an advisory capacity (Annex 2 to Res. 145 (Antalya, 2006)):
- the United Nations [CV/269A]
 - regional telecommunications organizations [CV/269B]
 - intergovernmental organizations operating satellite systems [CV/269C]
 - specialized agencies of the United Nations and the International Atomic Energy Agency [CV/269D]
 - DM-17/1004: Invitation from the ITU Secretary-General
 
 - Observers which do not participate in an advisory capacity (Annex 3 to Res. 145 (Antalya, 2006)):
- Sector Members referred to in CV/229 (recognized operating agencies, scientific or industrial organizations and financial or development institutions) and CV/231 (regional and other international telecommunication, standardization, financial or development organizations)
 - DM-17/1005: Invitation from the ITU Secretary-General
 
 
General information on organizational arrangements was sent in CL-18/33.
Information on organizational arrangements for Ministers and high-level delegates was sent in CL-18/29.