Invio digest giornaliero tramite cron riporta dei DeprecationWarning

L'invio giornaliero di un email con i principali eventi che accadono sulla piattaforma è affidato ad un cron.

Manualmente si può fare la stessa cosa con: python manage.py send_email_alerts

Nonostante le email arrivino agli utenti correttamente, mi ritrovo nel terminale i seguenti DeprecationWarning:

python manage.py send_email_alerts
/usr/lib/pymodules/python2.6/django/db/models/fields/subclassing.py:80: DeprecationWarning: A Field class whose get_db_prep_lookup method hasn't been updated to take `connection` and `prepared` arguments.
  new_class = super(SubfieldBase, cls).__new__(cls, name, bases, attrs)
/usr/lib/pymodules/python2.6/django/db/models/fields/subclassing.py:80: DeprecationWarning: A Field class whose get_db_prep_value method hasn't been updated to take `connection` and `prepared` arguments.
  new_class = super(SubfieldBase, cls).__new__(cls, name, bases, attrs)
/usr/lib/pymodules/python2.6/django/template/loaders/filesystem.py:58: DeprecationWarning: 'django.template.loaders.filesystem.load_template_source' is deprecated; use 'django.template.loaders.filesystem.Loader' instead.
  DeprecationWarning
/usr/lib/pymodules/python2.6/django/template/loaders/app_directories.py:71: DeprecationWarning: 'django.template.loaders.app_directories.load_template_source' is deprecated; use 'django.template.loaders.app_directories.Loader' instead.
  DeprecationWarning

Di seguito, per completezza, la configurazione che sto usando e che si trova in osqa/cron/send_email_alterts:

#!/bin/sh
PYTHONPATH=/percorso/alla/cartella/www
export PYTHONPATH
PROJECT_ROOT=$PYTHONPATH/osqa
/percorso/alla/cartella/env/bin/python $PROJECT_ROOT/manage.py send_email_alerts