Qt5, Windows 10: german Umlauten not correctly displayed

alainstgt

Porting from Qt 4.8 to 5.7 has raised a new issue: Umlauten inside a QString containing HTML code are not displayed correctly in a QLabel.
Following a code fragment;

mText = QString("<html><head>\
 <style type=\"text/css\">\
  .on{font: %1px Lucida Console; color: #FFFFFF;}\
  .off{font: %1px Lucida Console; color: #707070;}\
  .on2{font: %2 %1px Lucida Console; color: #FFFFFF;}\
  .off2{font: %2 %1px Lucida Console; color: #707070;}\
 </style>\
 </head>\
 <body>").arg(mLetterSize).arg(mLetterSize < 14 ? "" : "bold");
mText += QString("<DIV style= \"line-height: %1px;\">").arg(mLineHeight);
//  E S K I S T A F Ü N F
mText += "<SPAN class=\"on\">E S </SPAN>";
mText += "<SPAN class=\"off\">K </SPAN>";
mText += "<SPAN class=\"on\">I S T </SPAN>";
mText += "<SPAN class=\"off\">A </SPAN>";
mText += show_fuenf ? "<SPAN class=\"on\">F Ü N F</SPAN>" : "<SPAN class=\"off\">F Ü N F</SPAN>";
mText += "<br>";

Any idea how to solve the issue?

Thank you for your valuable time.
Alain