Você pode alterar a codificação da tabela através do shell:
$ manage.py shell
>>> from django.db import connection
>>> cursor = connection.cursor()
>>> cursor.execute('SHOW TABLES')
>>> results=[]
>>> for row in cursor.fetchall(): results.append(row)
>>> for row in results: cursor.execute('ALTER TABLE %s CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;' % (row[0]))
https://mayan.readthedocs.org/en/v0.13 /faq/index.html
