How to get previous state value using RTC dojo script
One answer
As far as I am aware, you can't access the history with the officially provided attribute customization JavaScript API. I think I have stated this fact about several dozen times in this forum.
If you dig deeper, you can probably do more. Keep in mind, using internal
APIs is frowned upon and support might not be able to help.
Here is an example where someone dug deeper and created something amazing: https://github.com/jazz-community/rtc-statushistory-presentation - it might not work in an Attribute Customization Script though.