This is a bug fix release. Importing employees would result in errors being thrown for saving phone numbers and addresses, due the fact that the pk of all models is now id.
There is a known issues with the employee page for adding phone numbers and addresses, then trying to set them as primary, which will cause that page to be reloaded as the submit hook is not registering correctly. To work around this issue, simply refresh the page after you have added and phone number or addresses, then check the primary checkbox.