WiredTiger has a runtime variable that enables the changes to the underlying page formats that support durable history content. That runtime variable is connected to the WiredTiger API level compatibility configuration settings. The API level configuration code was merged before the release that will enable those changes, and so the final release numbers were unknown.
This ticket is a placeholder to verify the release numbers are correct once they've been chosen.
See WT-4490 for details of the change.