+++ date = "2015-03-19T12:53:35-04:00" title = "Upgrade Guide" [menu.main] identifier = "Upgrade Guide" weight = 45 pre = "" +++
Key features of the 2.3 driver include:
- Implements Decimal128, a decimal floating-point numbering format that occupies 16 bytes (128 bits). See the [CRUD tutorial]({{< relref "tutorials/crud.md#specify-a-data-type" >}}) for an example.
Key features of the 2.2 driver include:
- Redesigned Connection Pool.
- Connection close will drain any outstanding operations.
- replicaSet parameter MUST be specified if using MongoClient to connect to replicaset, due to SDAM specification implementation.
- Domain support disabled by default, enable with parameter domainsEnabled on MongoClient or on the Server/ReplSet/Mongos.
Key features of the 2.1 driver include:
- Implements the new GridFS specification
- Implements support for the new 3.2 wire protocol level find, getMore and killCursor commands
- A growing/shrinking connection pool
- A worker-based connection pool which minimizes the impact of slow operations on throughput and latency when the number of slow operations is less than the number of connections in the pool
- Topology monitoring specification implementation, allowing applications to monitor the view of the topology as it changes
Key features of the 2.0 driver include:
- Adherence to the SDAM (Server Discovery and Monitoring Specification)
- Implementation of the CRUD Specification
- Performance improvements
- New JS-BSON parser which replaces the C++ extension
- A new core driver on top of which you can build alternative or experimental driver APIs
- APM (Application Performance Monitoring) API
See the [upgrading guide]({{<ref "upgrade-migration/upgrading.md">}}) on how to upgrade to 2.0