The variable `email_body_utf8` has been renamed to `email_body` during
PythonThreeTization but there is a leftover:
https://github.com/odoo/odoo/commit/200612ca1ef1#diff-85eeeed32c7f2fe285884f3661b49881R326
Backport of 63a4370afd
The variable `email_body_utf8` has been renamed to `email_body` during
PythonThreeTization but there is a leftover:
https://github.com/odoo/odoo/commit/200612ca1ef1#diff-85eeeed32c7f2fe285884f3661b49881R326
Backport of 63a4370afd