[traceback] UnserializableContentError: Control characters are not supported in XML 1.0 - /statuses.xml

[willkg]

https://sentry.prod.mozaws.net/operations/standup-prod/issues/645447/

UnserializableContentError: Control characters are not supported in XML 1.0
  File "django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "django/core/handlers/base.py", line 249, in _legacy_get_response
    response = self._get_response(request)
  File "django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "newrelic/hooks/framework_django.py", line 527, in wrapper
    return wrapped(*args, **kwargs)
  File "django/contrib/syndication/views.py", line 48, in __call__
    feedgen.write(response, 'utf-8')
  File "django/utils/feedgenerator.py", line 363, in write
    self.write_items(handler)
  File "django/utils/feedgenerator.py", line 397, in write_items
    self.add_item_elements(handler, item)
  File "django/utils/feedgenerator.py", line 429, in add_item_elements
    handler.addQuickElement("summary", item['description'], {"type": "html"})
  File "django/utils/xmlutils.py", line 20, in addQuickElement
    self.characters(contents)
  File "django/utils/xmlutils.py", line 27, in characters
    raise UnserializableContentError("Control characters are not supported in XML 1.0")

The problematic string is this one:

'<h3>servo</h3><p>Yesterday, got the Pathfinder SVG demo rendering the tiger (more or less�). Now starting work on the Pathfinder 3D demo.</p>'

I can't tell by looking at sentry, but I wonder if that's an emoji.