Meta bug for various url encoding fixes/backports.
Henry Castro committed a patch related to this issue. It has been pushed to "libreoffice-5-3": http://cgit.freedesktop.org/libreoffice/online/commit/?id=994fbbfc9669973015b1e0409df982b86a54cd8c&h=libreoffice-5-3 tdf#106274 wsd: fix sending wrong UTF-8 string to the client