Spring 23 – Track Field History for Activities (Task and Events)
As part of salesforce spring23 release Now, We can Track Field History for Activities (Task and Events)
See a list of changes to events and tasks after you turn on field history tracking in the Object Manager. Track up to six fields so that your team can see what’s changed in the Related tab for events and tasks. The Activity Record History component is automatically added to default event and task Lightning pages.
Refer Spring 23 Release Notes:
https://help.salesforce.com/s/articleView?id=release-notes.rn_customization_activity_field_history.htm&type=5&release=242
To Enable Field History to navigate the Object Manager and click the Set History Tracking under the Fields & Relationships
