Your sectors can now break down if you don't maintain them.

If they break down, they won't produce anymore and you won't be able to do any changes to them like buying/selling units or (de)activating it until you have repaired them.

The repairing costs are 125 euro per unit.

To avoid breakdowns you can maintain your units by hiring an engineer at the staff page.

EDIT: Repair costs are substracted from your daily earnings, so you will have some kind of tax advantage.