Which of the following is NOT a requirement for contractors regarding notices?

The statement that notices can only be sent by postal mail is not a requirement for contractors. This is correct because modern communication practices allow for greater flexibility in the means of delivering notices. Contractors are often allowed to send notices through various methods, including electronic communication like email, which is becoming increasingly common due to its efficiency and speed.

In contrast, the other options reflect important requirements that contractors must adhere to. Notices must be directed to specified contacts to ensure that communications reach the appropriate individuals who can take action or respond. Additionally, contractors are responsible for informing the relevant parties about any changes to their contact address so that notices and communications can be effectively delivered. This helps maintain clear and consistent communication throughout the contracting process.