Delete the Quote's deprecated Opportunity master-detail relationship field in Salesforce CPQ

Remove the Quote's deprecated 'Opportunity Master-Detail' relationship field by following the steps below:

1. Navigate to your Opportunity object.
2. Remove any reference to the Quote Count field.
3. Delete the Quote Count field.
4. Navigate to your Quote object.
5. Locate the discontinued Opportunity Master-Detail object: SBQQ__Opportunity__c. This field can now be deleted. Prior to doing so, you must migrate any reference in your own Apex classes, triggers, formula fields, or elsewhere from SBQQ__Opportunity__c to SBQQ__Opportunity2__c.
6. Delete SBQQ__Opportunity__c.
7. Add SBQQ__Opportunity2__c to your Quote Page Layouts.

Note: If an organization has pulled a field through this relationship to a SBQQ Managed Package field set and then upgrades the package, a stale reference will exist for this field in the field set for the Parent Object. The reference can be deleted using CLI and "data delete record" in data Commands. Contact Salesforce CPQ support if you need additional assistance.
Opportunity Master Detail cannot be deleted in Lightning Experience and needs to be deleted in Classic.