Migrating to Meteor 2.4

How to migrate your application to Meteor 2.4.

Most of the new features in Meteor 2.4 are either applied directly behind the scenes (in a backwards compatible manner) or are opt-in. For a complete breakdown of the changes, please refer to the changelog.

The above being said, there are a few items that you should implement to have easier time in the future.


Previously undocumented _ensureIndex has been aligned with MongoDB breaking change in naming and is now usable as createIndex. Use of _ensureIndex is now deprecated and will throw a warning in development for you.

Email 2.2

The email package had a feature update. You can now override the sending functionality completely with Email.customTransport or if you are using known services you can now ditch the MAIL_URL environment variable and set it in your settings.json file, like so:

  "packages": {
    "email": {
      "service": "Mailgun",
      "user": "postmaster@meteor.com",
      "password": "superDuperPassword"

Migrating from a version older than 2.3?

If you’re migrating from a version of Meteor older than Meteor 2.3, there may be important considerations not listed in this guide (which specifically covers 2.2 to 2.3). Please review the older migration guides for details:

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