Burkhard Domke (@BurkhardDomke) has posted four pictures by @mattcamby of Emirates 777-9s A6-EZA and A6-EZB and says they have been spotted in 4-door and 5-door configurations. he suggests that different aircraft are sharing the buzz letters "ZA" and "ZB" respectively.

The 777-9 seats 426 passengers in a typical two-class configuration, with a range of 7,285 nautical miles (13,500 km). The 777-9 will have the lowest operating cost per seat of any commercial airplane says, Boeing. The 777-8 seats 384 passengers with a range capability of up to 8,730 nautical miles (16,170 km). Boeing says that range is only just part of the story. The 777-8 also has the capacity to provide more revenue through more payload and improved fuel efficiency at both short and long ranges. This capability also allows the 777-8 to carry that increased payload at more challenging airports such as those constrained by high altitudes or hot temperatures.