Dynamic linking of external content in question variables (useful for feedback variables) and in question text (useful for inserting meclib areas)
castext() function for proper TeX formatting in dynamic strings (e.g. feedback)
Conditional text blocks
Upgrade to JSXGraph 1.4.4 (was 1.2.1 in STACK 4.3)
Migration problems
ev(expr, a=b, c=d,...) might fail. Workaround: use at(expr, [a=b, c=d,...]). Note that the equations need to be in a separate list. See github issue 830
Text with embedded CAS expressions like {@@} might requires either equations bracketed by \\\( \\\) or being explicitly set to HTML using paragraph tags. Sometimes even the whole widget must be set to HTML
Related to Maxima and unicode (if your Maxima isn't unicode-proof), for discussion and handling see STACK issue #832
Umlauts (äöüß) sometimes must be replaced by HTML codes: ä ö ü ß
Special characters like ° sometimes must be written as HTML code °
Related to Mathjax
Decorations in meclib labels must be bracketed. Instead of \\bar v write \\bar{v}.
Label placement in meclib images can be poor. Eventually "label" objects must be used.