I got this error in MongoDB 8.3.2:

$hash is not allowed in the current feature compatibility version. See https://docs.mongodb.com/master/release-notes/8.0-compatibility/#feature-compatibility for more information.

but there is no "#feature-compatibility" on that page.

And MongoDB 8.0 gives this error:

> db.adminCommand({setFeatureCompatibilityVersion: "8.2", confirm: true}) 

MongoServerError[Location4926900]: Invalid feature compatibility version value '8.2'; expected '7.0' or '7.3' or '8.0'. See https://docs.mongodb.com/master/release-notes/7.0-compatibility/#feature-compatibility.

Once again, the#feature-compatibility section seems missing from the linked page.

From a server documentation writer:

Well I think there could be a few things going on here after poking around a bit: * I'm not too familiar with the upgrade procedure enhancements at a granular level, but I'm thinking that maybe the target anchor was removed for more granular headings.

• This is a new 8.3 feature, which is odd that it points to the 8.0-compatibility page. I'm wondering if the FCV is set to 8.0 rather than 8.3, even though they're running 8.3 or if we have a hardcoded link that isn't quite getting the latest versioning scheme. See below for parallel theory:

Ultimately I wonder if this is meant to be a generic error message for FCV and the link intends to point to the setFeatureCompatibilityVersion page to check/update the FCV value. This page explains FCV and how to view the current setting, rather than anything about a specific feature. Unless I'm mistaken, we wouldn't have covered this new feature in the compatibility section. It seems like the solution here is to update the error message which I believe is an engineering task.

I think this should just be a generic error message that links to the setFeatureCompatibilityVersion page instead of any versioned release notes.