To give context, the setting I'm working on is one where advanced genetic engineering and biotechnology are plentiful.
The premise is this, the coffee industry is dominated in the tropics by a cartel that brooks no competition. So as a result one of the characters decides to go against this by taking a coffee plant and modifying it to be able to grow in temperate climes without the need of a hothouse or anything besides the local soil.
What changes would a coffee plant need to grow and flourish outside the tropics and still be consumable to humans?