"jquery-ui/ui/sortable" is a reference to jquery-ui version 11 only

[jaradc]

Just FYI:

                // AMD. Register as an anonymous module.
                define([
                        "jquery",
                        "jquery-ui/ui/sortable" // <-------------- this line
                ], factory );

https://github.com/ilikenwf/nestedSortable/blob/1bbc8184b9cfa8f5f5333ae6828b5d2cc2ead350/jquery.mjs.nestedSortable.js#L18-L22

Sortable is in jquery-ui/ui/widgets/sortable in jquery-ui version 1.12 and 1.13.