I want update existing system parameter in odoo 12, such as updating the default value 'b2c' of auth_signup.invitation_scope to 'b2b'. 

So I added the following code in ir_config_parameter.xml:

<odoo>

  <data noupdate="0">

    <record id="auth_signup.invitation_scopy" model="ir.config_parameter>

      <field name="key">auth_signup.invitation_scope</field>

      <field name="value">b2b</field>

    </record>

  </data>

</odoo>                                                                                                            

When I update addons, it did not succeed, error message:

Exception: Cannot update missing record 'auth_signup.invitation_scope'

odoo.tools.convert.ParseError: "Cannot update missing record 'auth_signup.invitation_scope'" while parsing /Users/odoo-dev/addons/customization/data/ir_config_parameter.xml:6, near
<record id="auth_signup.invitation_scope" model="ir.config_parameter">
<field name="key">auth_signup.invitation_scope</field>
<field name="value">b2b</field>
</record>