# List of notable changes made between 2.x and 3.0

All breaking changes must be described here. When adding a new entry,
always describe the impact on users and instructions for upgrading
applications from 2.x to 3.0.

See also https://github.com/strongloop/loopback/blob/master/3.0-DEVELOPING.md

## Always use bluebird as promise library

In version 3.0, we always use bluebird as our promise library
instead of `global.Promise`.
We consider Bluebird API a part of LoopBack API from now on,
you are welcome to use any Bluebird-specific methods in your applications.

If you are using LoopBack with a custom promise implementation provided
via `global.Promise`,
you will have to check all places where you are using non-standard promise API
and update them to use Bluebird API instead.

Please see [Related code change](https://github.com/strongloop/loopback-datasource-juggler/pull/790) here.