do-release-update crashes on lines 126-127

When I tried to upgrade my Xubuntu 14.10 to Xubuntu 15.04, I got a message:

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Проверка наличия нового релиза Ubuntu
Ваша версия Ubuntu больше не поддерживается.
Traceback (most recent call last):
  File "/usr/bin/do-release-upgrade", line 127, in <module>
    "%(url)s\n") % { 'url' : url })
ValueError: unsupported format character '?' (0xa) at index 55
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Then I searched through the internet and solved this problem. The solution for me was to edit with "gedit" file "/usr/bin/do-release-upgrade" and change lines 126 and 127:

From
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print(_("For upgrade information, please visit:\n"
 "%(url)s\n") % { 'url' : url })
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To
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print(_("For upgrade information, please visit:\n %(url)s\n") % { 'url' : url })
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And after that, do-release-upgrade successfully started upgrading Xubuntu.