Converting Bootstrap 3 to 4

Originally thought I would try a straight forward tutorial in Bootstrap but there were many issues that I encountered and apparently this is what happens when you do not filter your search results to a current date setting.

• The css styling in the tutorial, https://www.youtube.com/watch?v=gqOEoUR5RHg did not work for me without overriding existing rules from referenced bootstrap.min.css, i.e. need to use !important.
• Another issue popped up is that text is not sized or padded correctly inside the paragraph tag within the jumbotron class, fixed by upgrading to bootstrap version 4.0.0.
• Contrary to what this tutorial expressed have not seen any evidence of a change in font size when resizing screen under the jumbotron class
• Had a problem with the hide/show of elements due in part to my css and javascript references not in sync, tutorial uses Bootstrap 3 where class="collapse in" which replaced by class="collapse show" in Bootstrap 4.
• Well has been replaced by Card in Bootstrap 4 with no replacement for default gray background with rounded corners, need to use styling overrides.
• This tutorial uses Well to hide elements based on screen size. This does not work in Bootstrap 4. I used class="d-none d-lg-block".
• Dropdowns - need to add a reference to popper.js to get the dropdown to open and close. Also numerous issues with the <li> tag, does not work for alignment and disabled attribute in Bootstrap 4. Use just the <a> tag with classes like "dropdown-item" and "dropdown-item disabled." Another difference is the seperator does not work with the <li>, use the div tag with class="dropdown-divider." I also did some styling overrides to show underlines, bold for header text, and background color when item is active. So the progression of classes that works with <ul> is class="dropdown-menu" followed by <li> class="dropdown-item" all contained in a <div> where class="dropdown". Similar for horizontal dropdown where class="list-inline" and class"list-inline-item"
• ARIA - Accessible Rich Internet Applications
  The tutorial gave a screenshot of a URL reference that required some digging to not get a 404 error, page not found
  https://www.w3.org/TR/wai-aria/#aria-expanded - this should work to provide documentation to allow assistive technologies like screen readers to convey screen content for persons with disabilities.