RE: Dynamics 365 - Send notification when a check box is checked from list of a second field
How often you want to check and send this notification? Can it be daily or what sort of interval is acceptable to send the notification.
You can have a field on Case mark when the case was last checked for any changes.
Have a workflow that runs regularly - depending on the interval you want
In the workflow, you will have to do the following
01. Check if case fields have changed since last checked, compare the modified on with Last change check date, and if changed, and is subscription is on, then send email
02. Else, you will have to check all the related activities, for this, you will have to create a CWA to check if any changed since the last check, if so, send the email
Have a look at this code file I created to check if a case has any notes created : [View:https://github.com/Kokulan365/WorkflowEssentials/blob/master/Workflows/RecordHasNoteAttachment.cs:750:50]
Your CWA will have to check notes, posts, and activities and possibly other related entities if you want to include them as well