<script src=" https://code.jquery.com/jquery-migrate-3.3.0.js"></script>

It flagged using $ and to use jQuery. Every tutorial I could find using jQuery 3.5 still uses $ and not jQuery. Must I updated my all my code from $ to jQuery?

The other flag on this simple page was to replace .ckick with .on('click', )

Plus it flagged a things not in my page but in jquery itself,  like the following.

I reviewed  https://github.com/jquery/jquery-migrate/blob/master/warnings.md, but is there a quick reference of things that must be changed so code running in 1.12.4 will function in 3.5.1? 

My simple page does not work with the migrate code running.

2. <script type="text/javascript">
3. jQuery(document).ready(
4. function(){
5. jQuery('.trggr').on('click',function (e) {
6. jQuery(this).closest("tr").next().find('.moreinfo').slideToggle();
7. e.preventDefault();//prevent page from scrolling to top after click
8. return false;
9. });
10. }
11. );
12. </script>