XML : XML spreadsheed (Excel etc.): applying bold to a single word without to be compatible with WPS Office

In an Excel-like XML spreadsheet, a normal way of applying bold to a word is the <B> tag: to show

  This is a *bold* word    

the code is

  <Cell ss:StyleID="Default">      <ss:Data xmlns="http://www.w3.org/TR/REC-html40" ss:Type="String">          This is a <B>bold</B> word      </ss:Data>  </Cell>    

Is there another way of doing this, for example, via <Font> or style?

Motivation: I generate a spreadsheet in XML. Users may open it in Excel, OpenOffice, or other programs. One of them, WPS Office for Android, seems not to be able to show inline markup such as <I> or <Font html:Color="#FF0000">. In the XML file, WPS Office just ignores such markup (thus gracefully degrading to plain black text). However, it omits the text in <B>, so that instead

  This is a *bold* word    

the user sees

  This is a  word    

In Excel and OpenOffice the <B> tag works just as expected, but not in WPS Office. My goal is to generate a text that would show the bold words in other programs but at least gracefully degrade in WPS Office to plain text without omitting the bold words completely.