It’s all about the hundreds and thousands. There are some minor ICAO changes to radio phraseology that became applicable 8 November 2018.
|Application||Example||Transmitted as||What's changed?|
|Flight levels||FL 200||Flight level two hundred||Use hundred instead zero zero|
|Altimeter setting||1000||QNH one thousand||Use thousand instead of zeros|
|Transponder codes||2000||Squawk two thousand||Use thousand instead of zeros|