What version are you running? 22.214.171.124 What steps will reproduce the problem? Needs repository with ecoding different from utf-8 (for ex. koi8-r). What is the expected output? What do you see instead? In tap (for ex.) ViewDiff in place where must be cirilic symbols we can see only not readable symbols. What operating system are you using? What browser? Linux, Firefox Please provide any additional information below. reviewboard/diffviewer/diffutils.py convert_to_utf8 function returns unicode string in only case if codepage repository is utf-8. In other cases it returns basestring in code utf-8. For fixing propose change "return u.encode('utf-8')" by "return u" in case if uncode(s, 'utf-8') fails and repository has user encoding.