The mail does not increase in this factory

[Yona-TYT]

I decided to carry passengers and mail to this factory to see what happened.  The step time and i realized that the mail level never increase.
Is this a mistake? or is there any way to increase it?

[Ters]

Passenger and mail levels for buildings in general are static. I would assume that this applies to factories as well. (Although the definition for a factory actually contains two passenger levels, but only one mail level.)

[VS]

This factory does not need mail, thus the 0.

You can try sending them email

[Yona-TYT]

mmm .. I see, the factory not need  email for increase their production , that's why we never increases


thanks VS