Hello,

We offer several types of notifications.

To respect an initial due date, you can use unit indicators (global or by project)
Select the item you want to alert on, you select a value for a reminder and a value for an alert.
Then check the people who will receive an internal alert and / or an email from the choices offered.

Otherwise you can use the definition of notifications to trigger an alert by email.

You can customize each section using fields on the screen of the chosen element, help is available for each section.

Then build your query according to your expectations.
To respect an initial due date you can use $ {initialDueDate} followed by the equal (=) operator and the value to compare it to.

This can be a state for example, if the state is still "in progress" while the initial date has been reached ($ {initialDueDate} = $ {handled}), you will receive an alert on the email provided on this notification. It can also be a comparison with the planned end date different from the original due date ($ {initialDueDate} = $ {actualDueDate}) ...

A lot of possibilities according to your needs.
Then choose the values ​​of the alert and / or its frequency as well as the people who will receive this alert