Sales and invoice portal behavior was reorganized so customer-following logic now lives in the core sales and accounting areas, while website portal pieces move to the website portal sales area. The obsolete portal sale module and an overly broad email-recipient follower behavior were removed, reducing unnecessary automatic notifications and simplifying maintenance.

Task: https://www.odoo.com/web?#id=28619&view_type=form&model=project.task&action=327&menu_id=4720