Important: This is the documentation for the upcoming Feathers v5 (Dove). See for the current version.

# Migrating

This guide explains the new features and changes necessary to migrate to the Feathers v5 (Dove) release. It expects applications to be using the previous Feathers v4 (Crow). See the v4 (Crow) migration guide for upgrading to the previous version.

# Deprecations and breaking changes

# Core

  • Services are no longer Uberproto (an ES5 inheritance utility) objects and instead rely on modern JavaScript classes and extension. This also means service.mixin is no longer available.
  • The unofficial finally hook type is no longer available and should be replaced by the new asynchronous hooks which offer the same functionality using plain JavaScript:
  async (context, next) => {
    try {
      await next();
    } finally {
      // Do finally hook stuff here
  • The undocumented service._setup method introduced in v1 will no longer be called. It was used to circumvent middleware inconsistencies from Express 3 and is no longer necessary.
  • The undocumented app.providers has been removed since it provided the same functionality as app.mixins
  • app.disable, app.disabled, app.enable and app.enabled have been removed from basic Feathers applications. It will still be available in an Express compatible Feathers application. app.get() and app.set() should be used instead.

# Authentication

  • Grant upgrade
  • handleConnection update

# Asynchronous setup

service.setup, app.setup and app.listen now run asynchronously and return a Promise. This can be used to initialize database connections, caches etc. in the correct order and before the application starts. For more dynamic initialization flows, these methods can also be used with @feathersjs/hooks.

# Configuration

The automatic environment variable substitution in @feathersjs/configuration was causing subtle and hard to debug issues. It has been removed to instead rely on the functionality already provided by the underlying node-config, specifically the Custom Environment Variable support. To use existing environment variables add the following configuration file in config/custom-environment-variables.<json|yaml|js> like this:

// config/custom-environment-variables.json
  "hostname": "HOSTNAME",
  "port": "PORT",
  "someSetting": {
    "apiKey": "MY_CUSTOM_API_KEY"

# REST clients

  • The request library has been deprecated and request support has been removed from the REST client.
  • Since all modern browsers now support built-in fetch, the Angular and jQuery REST clients have been removed as well

# Primus transport

Due to low usage @feathersjs/primus and @feathers/primus-client have been removed from Feathers core and moved into feathersjs-ecosystem/feathers-primus. It will continue to work as is but rely on community support for future updates.

# Legacy socket format and timeouts

  • The legacy servicename::method socket message format has been deprecated in Feathers 3 and has now been removed. Use a v3 or later Feathers client or the current direct connection API.
  • The timeout setting for socket services has been removed. It was mainly intended as a fallback for the old message format and interfered with the underlying timeout and retry mechanism provided by the websocket libraries themselves.