Email Address is a mandatory field in 3.0

I have updated ZBSCRM to 3.0 today and now I can’t add new company/contact or edit existing ones where we don’t have email addresses. I am getting following errors:

Contact

Could not be saved
The value for the field: "Email" was not unique (exists) (Error #301)

Company

Could not be saved
The value for the field: "Main Email Address" was not unique (exists) (Error #301)

How can I make email address non-mandatory field for both properties?

Thank you.