Important notice: This page describes the "Google Apps release process," which applies to Gmail and Google Calendar, Contacts, Docs, and Sites. Google makes every effort to follow this process but does not guarantee it can or will do so at all times. Google also reserves the right to change the release process at any time. 
Google Apps release process
You have options for managing the release of new user and administrator features for your organization.
Releases for users
Want to try new features before your users get them?
Select the Scheduled Release track for your organization's Google Apps account.
Sign up for a separate Google Apps account (with a different domain name), which you'll use for trying out new features.
In your separate Google Apps account, uncheck the Scheduled Release track checkbox.
Release Process FAQ

Which Google Apps editions include the two release tracks for users?

Google Apps (free version), Google Apps for Business, and Google Apps Education. It's not available for Google Apps for Government.

Which Google Apps services are included in the release process?

The release process includes features for Gmail, Google Calendar, Google Contacts, Google Docs, and Google Sites. Features for all other Google Apps services, as well as Gmail and Calendar labs, are not included.

How long after the Rapid Release track does a new feature get added to the Scheduled Release track?

The time varies, depending on several factors, but the minimum time is one week.  

Can I switch between the two release tracks?

Yes, you can switch between the two tracks at any time. Note that it might take a day for the change to take effect.

Do I lose Rapid Release features if I switch to the Scheduled Release track?

Yes, if you switch to the Scheduled Release track, your users will no longer have access to features currently on the Rapid Release track. See which features are currently on the Rapid Release track.

How do I know when a feature is released on the Scheduled Release track?

We'll let you know in the Google Apps update alerts feed and on the Release Calendar one week before the release, on a Tuesday. We'll then follow up with another announcement on the day we release the feature.
Two release tracks for Google Apps features
Google Apps is 100% web, so your users receive new features -- such as a new feature in Gmail -- automatically, without your need to install or update any software. As a Google Apps administrator, though, you might want to delay the release of new features until after you train your support staff and tell your users about the coming changes. That's why our two-track release process lets you choose when your users receive new features:
Rapid Release track: Choose this track if you want your users to access new features as soon as Google rolls them out to production. These features have been through testing and quality assurance and are available to Google's consumer users (free users).

Scheduled Release track: Choose this track if you'd rather hold back new features from users temporarily so you have time to prepare them for the changes. Google releases features to the Scheduled Release track on Tuesdays only, at least one week after the feature was released to the Rapid Release track.
Important: If you switch to this track, your users won't have access to any features currently on the Rapid Release track. Make sure you first check the list of Rapid Release features.
The Rapid Release and Scheduled Release tracks include only the following Google Apps services:
Gmail
Google Calendar
Google Contacts    
Google Docs
Google Sites

Features for all other Google Apps services, as well as and labs for Gmail and Calendar, are not included.
Get instructions for setting up your release track
Multiple language support: Google releases most features to both the Rapid Release and Scheduled Release tracks in multiple languages.
How it works: an example
Google releases a new Gmail feature simultaneously to the Google Apps Rapid Release track and to consumer users (free users) on a Wednesday. If you selected the Rapid Release track, your users can access the feature now. The Google Apps update alerts feed and the Release Calendar notify you about this feature on the day it's released.
On the next Tuesday, Google evaluates the feature and determines that it's ready for release to Google Apps customers. That day, Google announces the planned release in the Google Apps update feed and on the Release Calendar.
On the following Tuesday (one week later), Google releases the Gmail feature to the Scheduled Release track. If you selected this track, your users can now use the feature. The Google Apps update feed and the Release Calendar confirm the release.
Example only:
Releases for administrators
Two options for updating your control panel
As a Google Apps administrator, you can choose how quickly you want to receive new features for your administrator control panel. Here are your options:
Next Generation: You'll receive all features for your control panel immediately after Google releases them. With this option, you'll get the new features earlier than with the Current version control panel, but they'll be in English only. All features in the Next Generation control panel are later released to the Current version control panel.
Current version: You'll receive all new features for your control panel after Google localizes them in multiple languages. Choose this option if you'd rather wait for features until after they're available in your primary language.
Note: The length of time before a feature is moved from the Next Generation control panel to the Current version control panel can vary, depending on the complexity of the feature, localization requirements, and other factors.
Multiple language support: Google releases most features to the Current version control panel in multiple languages.
Migration tools and API releases
Google also releases new migration tools, APIs, and features for administrators and developers that aren't part of the administrator control panel. You'll be notified of these products and features in the Google Apps Updates feed and on the Release Calendar on the day they're released.
Multiple language support: Google releases most migration tools and APIs (and their documentation) in English only.