What is the main topic of this announcement? [originaltext]Attention, all employ

Attention, all employees.  A new security system will be installed over the weekend. This means   starting on Monday, all employees will be required to carry identification cards. They will be used to enter and exit the building. You will need to place your card on the security panel in order for the door to be open. If you do not have the card, doors will not open and you will not be able to enter or exit the building. In addition to that, all guests are also required to visit the security care office to get temporary cards before entering the building. If you’ d like to receive your identification card by Friday, please contact your manager to confirm we have your information correctly.