What version are you running?
2.5.2
What steps will reproduce the problem?

Configure a JIRA
Configure a Repository von RB so use that JIRA
Add a ticket to jira with non-ascii summary/title like German umlauts: äöü
Use that ticket number in RB
Try to show information in RB about that ticket


What is the expected output? What do you see instead?
Expected: See jira information
Actually:
Traceback (most recent call last):

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/core/handlers/base.py", line 112, in get_response

    response = wrapped_callback(request, callback_args, callback_kwargs)

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/reviewboard/reviews/views.py", line 1684, in bug_infobox

    'bug_summary': bug_summary

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/shortcuts/init.py", line 29, in render_to_response

    return HttpResponse(loader.render_to_string(*args, kwargs), *httpresponse_kwargs)

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/template/loader.py", line 164, in render_to_string

    return t.render(Context(dictionary))

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/template/base.py", line 140, in render

    return self._render(context)

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/template/base.py", line 134, in _render

    return self.nodelist.render(context)

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/template/base.py", line 840, in render

    bit = self.render_node(node, context)

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/template/base.py", line 854, in render_node

    return node.render(context)

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/template/base.py", line 897, in render

    return render_value_in_context(output, context)

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/template/base.py", line 875, in render_value_in_context

    value = force_text(value)

  File "/opt/reviewboard/dist/lib/python2.7/site-packages/django/utils/encoding.py", line 108, in force_text

    s = six.text_type(bytes(s), encoding, errors)

UnicodeEncodeError: 'ascii' codec can't encode character u'\xf6' in position 9: ordinal not in range(128)