Zuora 360 by default only syncs the latest version of a Subscription and deletes the old version, therefore your Invoice Item in Salesforce could have a null lookup to the SRPC if generated based on a...Zuora 360 by default only syncs the latest version of a Subscription and deletes the old version, therefore your Invoice Item in Salesforce could have a null lookup to the SRPC if generated based on a previous Subscription version. When you enable the feature of upserting Salesforce Subscriptions instead of deleting the old versions in sync, an Invoice Item in Salesforce will have a lookup to an SRPC even if this Invoice Item was generated from an old version of a Subscription.