We formalized the usage of FeatureFlag::isEnabledAndIgnoreFCV() in https://jira.mongodb.org/browse/SERVER-66587. Now every usage of FeatureFlag::isEnabledAndIgnoreFCV() is changed to FeatureFlag::isEnabledAndIgnoreFCVUnsafe() and ask the engineer to add a comment describing why you have to ignore FCV here.

Overall, we expect places that are using FeatureFlag::isEnabledAndIgnoreFCVUnsafe() now to be:

• isEnabledAndIgnoreFCVUnsafeAtStartup() if this feature flag check is before FCV initialization.
• Stay isEnabledAndIgnoreFCVUnsafe() if you have a reason, and update your reason in the comment line starting with (Ignore FCV check):
• Change to isEnabled(FCV).

You can also search for TODO(SERVER-75389) for all places need to revisit