According to FIVB, the participants of World Cup 2019 have been officially confirmed.
Feel bad for European teams, they will have to finish Euro Championship on Sep 29, then World Cup starts on Oct 1. or that might means some European teams need to drop either of it to play with 2rd squad.
• Men's 2019 FIVB World Cup:
World Champion: Poland
Asia: Iran & Australia
Africa: Egypt & Tunisia
Europe: Italy & Russia
North and Central America and Caribbean: USA & Canada
South America: Brazil & Argentina