This change lets Odoo show clearer debugging information when running in development mode instead of hiding errors behind normal exception handling. It helps developers diagnose website and server issues faster, with only internal impact for production users.

...kzeug debugger

The contact birthdate field is now stored as a proper date instead of free-form text. This improves data consistency and can make reporting, validation, and integrations involving birthdays more reliable.

#2531 change data-type char to date for birthdate field in base module