The Address class in scim2_models/resources/user.py defines the primary attribute for addresses, but that attribute is not present in the default-schemas.json the scim2_server project.
Trying to POST a new User object with an address.primary attribute results in an error "Extra inputs are not permitted".
Adding the following attribute definition right after 'type' seems to fix this.
{
"name": "primary",
"type": "boolean",
"multiValued": false,
"description": "A Boolean value indicating the 'primary' or preferred attribute value for this attribute. The primary attribute value 'true' MUST appear no more than once.",
"required": false,
"mutability": "readWrite",
"returned": "default"
}