Screenshots
This calculated field returns the number of times the Expected delivery date-time field has been changed.
Create a new Calculated Number Field (by JWT) custom field and name it properly.
Providing a description will help you to identify what the custom field does but this step is optional.
Add the following expression:
count(fieldChangeTimes({issue.cf10201},^0 != ^1))
{issue.cf10201} is the field code for the Expected delivery date-time field.
{issue.cf10201}
Choose Number
Choose ### days
Check the parameter Uninitialized when calculated value is zero
Add the field to the relevant view screens.
Remember: All calculated fields are read-only and cannot be manually updated on a create or edit screen.
Check the results
Once configured and added to an issue screen (a parent issue ), the result will look like this:
SCREENSHOT