Details
Description
Verify that during the upgrade the commands with readConcern level:snapshot are rejected.
Summary:
- Verify that snapshot read concern is rejected when the cluster is not fully upgraded and then allowed in FCV 3.6 and 4.0 once each binary has been upgraded.
Design:
- Copy the existing jstests/multiversion/cluster_upgrade.js test, and add assertions on the behavior of snapshot reads at each stage.