null as an array offset is deprecated in php 8.5

"Using null as an array offset or when calling array_key_exists() is now deprecated. Instead an empty string should be used."

Using null as an array offset or when calling array_key_exists() is now deprecated. Instead an empty string should be used.
https://www.php.net/manual/en/migration85.deprecated.php#migration85.deprecated.core.using-null-as-an-array-offset

The following JavaScript dependencies are updated
jQuery to 4.0.0
jQuery-UI to 1.14.2
jQuery plugins to their latest available versions (although they have been abandoned for years).
jquery.jec-1.4.0
jquery.scrollTo-2.1.3
jquery.tipped-2.2b

Implement changes suggested by the migration script jquery-migrate-4.0.2.js
Mostly replacing blur, click, dblclick, focus, key*, mouse* shorthand functions
with on() and trigger() calls appropriately.
Replaced jQuery.trim() with String.trim().

The buttons in the dialogs were changed at some point from input with
span to plain button elements with no parent input. But the JavaScript
code updating the dialog still used the span element in the find calls,
and the buttons were not updated as the result.
This issue should now be fixed, the buttons Guided / Expert mode,
Back, Next in the dialogs should update based on the current step.