For those of you not usually reading any of the above, please read at least the first item, that says:
"This is important if you’re upgrading from earlier versions!
To update your code for version 3.11 references, replace the following URLs:
/3.11/ (note the dropped “/js/dojo”) and change
/3.11/esri/ (note the dropped “/js”).
An example of this is shown below
<link rel="stylesheet" href="http://js.arcgis.com/3.11/dijit/themes/claro/claro.css">
<link rel="stylesheet" href="http://js.arcgis.com/3.11/esri/css/esri.css">