Aptify generates Opportunity History records automatically using Aptify's Process Pipeline technology. Specifically, the system uses the Generate Opportunity History process flow, which is fired by the BeforeSave event for the Opportunities service.
Generate Opportunity History Process Flow 
This process flow uses the Generate Opportunity History process component, which has a TriggerFileList input property. When this property is blank (as it is in the Generate Opportunity History process flow), the component uses the trigger list defined in the Opportunities entity's HistoryTriggerFieldList attribute.
An administrator can review the details of this attribute on the Opportunities entity's Configuration > Attributes tab. Note that the default HistoryTriggerFieldList includes the TotalMinAmount, TotalMaxAmount, and TotalEstAmount fields. However, changes to these fields do not trigger the creation of a History record since these fields are updated by the OpportunityDetails sub-type entity's trUpdateOppDetail and spUpdateOppSummaryFields database objects.
HistoryTrigger FieldList Attribute 
If an organization needs to modify the list of fields that trigger the creation of Opportunity History, an administrator can either define a trigger list in a Process Flows record that implements the Generate Opportunity History component (by specifying a commadelimited string of fields for the TriggerFileList property) or modify the field list in the HistoryTriggerFieldList entity attribute.
Note the process component also supports the following optional input properties:
- TriggerOnNew: If set to 1 (the default), the a History record is generated when a new Opportunities record is saved.
- UpdatedByID: An administrator can use this property to specify a particular employee to use as the Updated By employee when generating History records. In the standard process flow, this property is set to -1 and the system automatically populates the Updated By field using the Employees record linked to the current user who modified the Opportunities record.