Downgrade 4.4 to 4.2
On this page本页内容
The following page summarizes various considerations for downgrading to 4.2. For specific instructions for your deployment type, see:
- Downgrade 4.4 Standalone to 4.2.
- Downgrade 4.4 Replica Set to 4.2.
- Downgrade 4.4 Sharded Cluster to 4.2.
Downgrade Path
Before you upgrade or downgrade a replica set, ensure all replica set members are running. If you do not, the upgrade or downgrade will not complete until all members are started.
If you need to downgrade from 4.4, downgrade to the latest patch release of 4.2.
MongoDB only supports single-version downgrades. You cannot downgrade to a release that is multiple versions behind your current release.
For example, you may downgrade a 4.4-series to a 4.2-series deployment. However, further downgrading that 4.2-series deployment to a 4.0-series deployment is not supported.
Downgrade Floor
If you need to downgrade from version 4.4, downgrade to 4.2.6 or a later version. You cannot downgrade to 4.2.5 or an earlier version.
Create Backup
Optional but Recommended. Create a backup of your database.
Downgrade Feature Compatibility Version (fCV)
Before downgrading the binaries, you must downgrade the featureCompatibilityVersion (fCV) to "4.2".
Remove Backwards Incompatible Features
Before downgrading the binaries, remove all persisted 4.4 features that are incompatible with 4.2.