Compatibility Changes in MongoDB 7.1

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Backward-Incompatible Features

Deprecated Parameters
General Changes

Important

MongoDB 7.3 is a rapid release and is only supported for MongoDB Atlas. MongoDB 7.3 is not supported for use on-premises. For more information, see MongoDB Versioning.

Backward-Incompatible Features

Starting in MongoDB 7.1, MongoDB doesn't round the capped size of non-oplog capped collections up to the nearest integer multiple of 256, in bytes.

Capped collections with a size that is not a multiple of 256 bytes are not compatible with earlier versions of MongoDB. To downgrade from MongoDB 7.1 to an earlier version, you must remove or resize the collection. To learn how to resize a capped collection, see Resize a Capped Collection.

Deprecated Parameters

MongoDB 7.1 deprecates the following server parameters:

Deprecated	Description
`minNumChunksForSessionsCollection`	Deprecated in version 7.1. MongoDB 7.1 deprecates the `minNumChunksForSessionsCollection` server parameter. Starting in MongoDB 7.1. the `config.system.sessions` collection is no longer presplitted during balancing rounds. You cannot use `minNumChunksForSessionsCollection` to guarantee a minimum number of chunks for that collection.

General Changes

UpdateOne `upsert` Behavior on Sharded Collections

Starting in MongoDB 7.1, when using updateOne() with upsert: true on a sharded collection, you do not need to include the full shard key in the filter.

Deprecations

Deprecated	Description
`getAuditConfig`	MongoDB 7.1 deprecates the `getAuditConfig` command. Use the `auditConfig` cluster parameter instead.
`setAuditConfig`	MongoDB 7.1 deprecates the `setAuditConfig` command. Use the `auditConfig` cluster parameter instead.

Renamed `serverStatus` Metric

Starting in MongoDB 7.1, the serverStatus metric countDocsClonedOnDonor is now shardingStatistics.countDocsDeletedByRangeDeleter.

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