Uncaught TypeError: $.widget.extend is not a function when using JQuery UI 1.11.4

Uncaught TypeError: $.widget.extend is not a function when using JQuery UI 1.11.4

I am going to upgrade JQuery UI to 1.11.4 from 1.8.17 in my project.
But I got the error when loading page:
Uncaught TypeError: $.widget.extend is not a function

I saw this error in Chrome -> Console.

In original page, JQuyer 1.6.4 and JQuery UI 1.8.17 are used.
After upgrading JQuery UI to 1.11.4, I got the error in $.Widget.prototype.
Please refer to picture below.
Is JQuery UI 1.11.4 compatible with JQuery 1.6.4?
Any other coding or configuration needed to fix this problem?

Thanks.