Even as Microsoft has quietly begun the Lumia Denim firmware updates in parts of Europe and Asia, including India, it has also made a change to its North American support website. The site no longer lists the current status of upcoming firmware releases for each device and carrier in the US and Canada.
Previously, the site listed the status of firmware updates such as Lumia Black and Lumia Cyan as " Available", "Under Testing", or "Under Development" for Microsoft's Windows Phone devices. Now that has been changed to simply showing the currently available firmware release for each device.
It's likely this change is in preparation for the eventual launch of Lumia Denim updates in North America, so when that happens we should quickly know which devices and which carriers are getting that update.
Source: Microsoft Mobile Thanks to Jordan for the tip!