One of the nice things about Microsoft Dynamics CRM's roll-up fields is the ability to capture the latest date of related underlying records. In the past, we were able to create a Date field in the Contact entity and populate it with the Last Activity Date. Previously, you could only find Activities that were related to the Contact via the Regarding (regardingobjectid) field. However, with new versions of MSCRM come updated capabilities.
The latest MSCRM 2016 version allows you to find Activities related to other entities via the Activity Party records. You can include Activities where the Contact (for example) is entered in the "To Recipient" or "CC Recipient" or "Required Attendee" field. They no longer have to be in the Regarding field for the Roll-up to work.
Here's a look at how to configure your Last Activity Date Roll-up field.
When creating a new field, change the DATA TYPE to "Date and Time". Then select "Roll-up" for the FIELD TYPE.
Now click the Edit button.
When doing this for the Contact Entity, your SOURCE ENTITY will automatically be "Contact". Under RELATED ENTITY, choose "Activities (Regarding)".
Once you do this, you will then see your FILTERS and a new section called "INCLUDE INDIRECTLY RELATED ACTIVITIES". This is where the magic happens.
First set your FILTER to only include Completed Activities and then, under "INCLUDE INDIRECTLY RELATED ACTIVITIES", select "Activity Parties (Activity)" as your Activities Related via Entity. Once done, you will see another FILTERS option.
To include Activities associated to the Contact via Activity Parties, select which Participation Type you want to include under this filter. I have selected "To Recipient" and "Required Attendee".
Last thing to do is set your Aggregate. Select MAX for the (Activity) Actual End field. This will return the latest date of all completed activities where the Contact is in the regarding field or an activity has the Contact in either the "To" field or the "Required Attendee" field.
Microsoft keeps upgrading their product and adds much needed functionality along the way. I hope this helps in your quest for automating roll-up of data.
Beringer Associates, a Microsoft Gold Certified Partner, is always here to provide expert knowledge in topics like these. Please contact us with any questions you may have.