[slowsmile]

@Doitsu & @KevinH...Just tried Doitsu's Polish HTML LibreOffice file in my plugin and it displays Polish characters without a problem in Sigil Text View. So my conversion is correctly converting to unicode utf-8. You can also verify this for yourself because I've used the current version of my plugin(v0.2.5) to test the Polish file.

I should also add that I've only just put in a fix(which is in v0.2.5) whereby I now obtain the locale language and insert that into the xml:lang attribute in the XMLNS for every html file in the epub. This might have something to do with why my plugin now works for different language charsets.

If my fix has cured the character set problem then does that also mean that the Sigil app interrogates the XMLNS xml:lang attribute to ascertain the correct language charset whenever you open an epub or html file in Sigil?

UPDATE: I've just checked the Polish epub more thoroughly again and found errors in the contents.xhtml(no TOC), content.opf and toc.ncx files -- that's probably because I did not insert the xml:lang in the XMLNS for those files. I also need to add the correct dc:language to the metadata as well. I think that these errors also more or less confirm that the Sigil app does indeed interrogate the xml:lang attribute. I'll try and put in a fix to confirm this later.