Provide synchronization point once upgrades have been checked
As #6592 (closed) shows, at least our automated test suite needs to know when upgrades have been checked. A simple mechanism, similar to htpdate’s “done file”, would be good enough for the time being.
Feature Branch: feature/6508-incremental-upgrades-phase-four
Parent Task: #6508 (closed)
- Blocks #6592 (closed)