The following table lists changes in the documentation to support each release.

Spring 2020 Rev AApproval System PropertiesModified topic. Added information about Queueable Apex Batch Size system property. 
Spring 2020Submitting a Request with AttachmentsModified topic. Added information for grouping multiple documents across multiple agreement records.

Creating Search Filters (Approvals)

Modified topic. Added information for character limit increase for Approval Search Filters.

Modified topic. Added information for support added after scalability improvement.

Upgrading Intelligent Workflow Approvals

New topic. Added information about how to upgrade Intelligent Workflow Approvals.
Winter 2019 Rev ASetting up Backup or Delegate ApproversModified topic. Added information about email notifications for delegate approver. 
Winter 2019Creating An Approval ProcessModified topic. Added information for creating an adhoc approval process.

Setting Up An Adhoc Approval Process in RuntimeNew topic. Added info for setting up an adhoc approval process in runtime.

Creating Approval StepsModified topic. Added information for selecting Carbon Copy assignees. Added reminded jobs information.

Setting Up Backup and Delegate Approvers

Modified topic. Added info to create multiple entries for Backup/Delegate records.

Approvals and My Approval PagesModified topic. Added information for removing an adhoc approver from the my approvals page.

Approval System Properties

Modified topic. Added new system property "Cancellation Email to Approved/Notified" flag and its description.

Summer 2019

Custom Query Callback for Reassigning and Adding Approver

Modified topic. Added information for reassigning approver.

Setting Up a Backup or Delegate for Out-Of-OfficeNew topic.

Creating Approval StepsModified topic.

Creating An Approval ProcessModified topic.

Setting Up Backup and Delegate ApproversModified topic.

Approval Email Notification TemplatesModified topic.

Approval and My Approval PagesModified topic.
Spring 2019N/ANo new topics were added.

Winter 2018

Configuring CPQ Approval WorkflowModified topic. Added information for Standard Approval Step and Approval Rule Entry Step.