How to disable the Password Changed email

There is a built-in email template "Password Changed" in WordPress:

Hi ###USERNAME###,

This notice confirms that your password was changed on ###SITENAME###.

If you did not change your password, please contact the Site Administrator at
###ADMIN_EMAIL###

This email has been sent to ###EMAIL###

Regards,
All at ###SITENAME###
###SITEURL###

This is not an Ultimate Member email template. This is a built-in WordPress email template that WordPress sends if a new password does not match an old password on the user data update.

You can use the send_password_change_email hook to disable this email. Just add this code to the file functions.php in the active theme directory.

// Disable the "Password Changed" email.
add_filter( 'send_password_change_email', '__return_false' );