This example shows how to set up MathJax version 3 to act somewhat more like MathJax version 2.
The main actions are to return the \color macro to the non-standard version-2 behavior, and to modify the \require macro to convert the version-2 TeX extension names into the corresponding version-3 names.
In addition, this example also defines versions of
that you may be able to use to keep custom code that uses these version 2 features working. It also defines
to generate error messages and looks for
<script type="text/x-mathjax-config">
...
</script>
blocks, which are no longer supported, in order to alert you to the need to convert these to version 3 by hand.
You should use the configuration converter to help convert your version 2 configuration to a comparable version 3 configuration.