The CRM module was reorganized and migrated to Odoo's newer internal API while aiming to keep existing business behavior unchanged. This should improve maintainability and test coverage, with little visible impact for day-to-day CRM users.

Migration of CRM code to new API. Nothing should change functionnaly.
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The partner assignment area in CRM was updated to use Odoo's newer internal framework and file structure. This should make the module easier to maintain and more reliable over time, with no major visible workflow changes expected for users.

Task: https://www.odoo.com/web#id=12139&view_type=form&model=project.task&action=327&menu_id=4720