@Nick_1964 : a great way to achieve correct hyphenation in epub or kepub (which I used before 3.16 but is now correct in french and in english, for I can see of it) is to use kobo_extra.css at the root of your kobo device, with :
Code:
body {adobe-hyphenate: explicit !important;} /*epub*/
Code:
body { -webkit-hyphens: manual; } /*kepub*/
checking ‘modify css’ in kobotouch or kobotouchextended plugin and hyphenating the book manually using the 'hyphenate this’ calibre plugin with the
dutch hyphenation dictionary of openoffice.org installed inside. This way, the hyphen algorithm of the kobo is not use at all, but you will get correct hyphen for all your books.
You can also install the dutch dict in your kobo (and trying to use the hyphen algo of your kobo) by using two alternative methods (the
KoboRoot.tgz update or
frostschutz method).
There is an hyphen dict is included in the kobo firmware, named hyph_nl.dic, check the <dc:language>nl</dc:language> tag included in the book’s content.opf to see if the language code is correct.