Important
These instructions apply to self-managed deployments. To change the MongoDB version on an MongoDB Atlas cluster, see Change the MongoDB version. If you manage your deployment with Ops Manager or Cloud Manager, change the MongoDB version using the application's upgrade procedures instead.
Starting in MongoDB 8.3, you can downgrade your MongoDB version to the immediately previous minor or major version.
Downgrade Path
If you need to downgrade from 9.0, downgrade to the latest patch release of 8.3.
MongoDB supports single-version downgrades along adjacent versions only. You cannot downgrade to a release that is multiple versions behind your current release.
For any MongoDB release, you can upgrade or downgrade to the immediately previous major or minor version.
Feature Compatibility Version and Downgrade
The setFeatureCompatibilityVersion command supports downgrading the FCV from 9.0 to "8.3".
Follow the FCV downgrade steps in each procedure to ensure your deployment runs with a feature compatibility version that is supported by the target MongoDB version.