ubuntu-16.04.1 mysql "Incorrect string value"

Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/mysql/base.py", line 110, in execute
    return self.cursor.execute(query, args)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/cursors.py", line 250, in execute
    self.errorhandler(self, exc, value)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/connections.py", line 42, in defaulterrorhandler
    raise errorvalue
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/cursors.py", line 247, in execute
    res = self._query(query)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/cursors.py", line 411, in _query
    rowcount = self._do_query(q)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/cursors.py", line 374, in _do_query
    db.query(q)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/connections.py", line 270, in query
    _mysql.connection.query(self, query)
_mysql_exceptions.OperationalError: (1366, "Incorrect string value: '\\xF3\\x88\\x9B\\xAF.\\x0A...' for column 'annotation' at row 1")

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 367, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 359, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 294, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 345, in execute
    output = self.handle(*args, **options)
  File "/home/gregor/sopds/opds_catalog/management/commands/sopds_scanner.py", line 53, in handle
    self.scan()   
  File "/home/gregor/sopds/opds_catalog/management/commands/sopds_scanner.py", line 67, in scan
    scanner.scan_all()
  File "/home/gregor/sopds/opds_catalog/sopdscan.py", line 81, in scan_all
    self.processzip(name,full_path,file)
  File "/home/gregor/sopds/opds_catalog/sopdscan.py", line 106, in processzip
    self.processfile(n,file,z.open(n),cat,1,file_size)
  File "/home/gregor/sopds/opds_catalog/sopdscan.py", line 165, in processfile
    book=opdsdb.addbook(name,rel_path,cat,e,title,annotation,docdate,lang,file_size,archive)
  File "/home/gregor/sopds/opds_catalog/opdsdb.py", line 121, in addbook
    cat_type=archive,avail=2, lang_code=getlangcode(title))
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 399, in create
    obj.save(force_insert=True, using=self.db)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/base.py", line 796, in save
    force_update=force_update, update_fields=update_fields)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/base.py", line 824, in save_base
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/base.py", line 908, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/base.py", line 947, in _do_insert
    using=using, raw=raw)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/query.py", line 1045, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/sql/compiler.py", line 1054, in execute_sql
    cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/local/lib/python3.5/dist-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/mysql/base.py", line 110, in execute
    return self.cursor.execute(query, args)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/cursors.py", line 250, in execute
    self.errorhandler(self, exc, value)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/connections.py", line 42, in defaulterrorhandler
    raise errorvalue
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/cursors.py", line 247, in execute
    res = self._query(query)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/cursors.py", line 411, in _query
    rowcount = self._do_query(q)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/cursors.py", line 374, in _do_query
    db.query(q)
  File "/usr/local/lib/python3.5/dist-packages/MySQLdb/connections.py", line 270, in query
    _mysql.connection.query(self, query)
django.db.utils.OperationalError: (1366, "Incorrect string value: '\\xF3\\x88\\x9B\\xAF.\\x0A...' for column 'annotation' at row 1")