To use this functionality on Smart Checklist versions older than v5.0.0, you need to set-up "Checklists" custom field / Check instructions here: Custom Fields
To track changes in Smart Checklist, switch to the History tab of your Jira item.
History of Smart Checklist changes is tracked due to the "Checklists" custom filed. Read about custom fields.
Since “Checklists“ is just a custom field - you get a full view of all available history log values, such as:
Who made changes
Original value
New value
For any questions or feature requests contact us: smartchecklist@railsware.com