.size()
Note: This method has been removed in jQuery 3.0. Use the .length property instead.

.andSelf()
Note: this API has been removed in jQuery 3.0; use .addBack() instead, 
      which should work identically.

.isFunction()
Note: As of jQuery 3.3, jQuery.isFunction() has been deprecated. 
      In most cases, its use can be replaced by typeof x === "function".

:eq() Selector
Note: As of jQuery 3.4, the :first pseudo-class is deprecated. 
      Remove it from your selectors and filter the results later using .first().
:first Selector
Note: As of jQuery 3.4, the :first pseudo-class is deprecated. 
      Remove it from your selectors and filter the results later using .first().