All output XML is encoded as UTF-8. To present non-ascii characters you will have to use a font that support the characters/glyphs you want.
On the reports servers we currently support a font called Unifont (http://unifoundry.com/unifont.html) which supports most of the multibyte space of glyphs.
To use this from XF designer add this to the font-family like shown in picture below. Specifying both at "normal" font and the unifont in the same family will make the renderer go to unifont for all glyphs that is not found in the first font.
The quality of the Unifont is not great and also might not suite you language, so it might be necessary to use a different font. Pleas contact us if you need to install this on the server.
Referencing characters in Wingdings and other special fonts
Some fonts need to reference glyps with their Unicode entity. XF Designer does not support this and will reference the font with a normal ascii character, which the server side generation (FOP) does not support.
To reference those chars you need to swap out the normal char with the unicode char. First you need to find the unicode code for the glyph, e.g. by looging in https://www.myfonts.com/fonts/ascender/wingdings/1/ you will see
Take a copy of the "HTML entity" value
Go to the "Text View" (Home tab) and replace normal characters with the Unicode code. Example below shows both.
and will result in this.