I have upgrade WordPress but I do not like Gutenberg editor. If you do not know what it is be happy. It is a block WYSIWYG HTML editor for pages and articles. I had to disable this feature and restore the classic editor. This is only for instructors.
If you are an instructor on this website you can post articles with code. Now you can use HTML – edit to modify <pre> block with class: <pre class=”prettyprint”> to enable Google prettify plugin to highlight your code paragraph.