This page has information about the latest version of the character controller:
opsive.com
This update contains some required changes so be sure to check the link.

Ultimate Character Controller 2.3.1 Released - Opsive
Version 2.3.1 of the Ultimate Character Controller is making its way to the Opsive Store and the Asset Store. Note: The Unity Package Manager doesn’t . . .

This update contains some required changes so be sure to check the link.