The Lumia Denim update is like a glacier melting, slowly but surely happening. Microsoft have been quite forthright about updates saying "early 2015", which for some means January 2 at 12:01 am, for others by March 1. Indeed, every day we are getting random tips from people around the globe noting they now have the update.
India is arguably one of the largest Windows Phone markets, but so far only the Lumia 520 has Denim in that country.
Now, Microsoft India in personally responding to many inquiries that all eligible Lumias should have the update by the end of the month.
Going further, we can even read the Twitter account's responses as suggesting that all Lumias, worldwide, should be updated by the end of February. This release would keep in timing with Microsoft's "early 2015" estimate and seems plausible giving the amount of time that has passed.
However, we should remind users that, technically speaking, what you know as Lumia Denim is nothing more than some OS fixes and improvements for non-PureView phones. In other words, only the Lumia 830, Lumia 930 and Lumia 1520 are getting the major new features like 'Hey Cortana' and the new Lumia Camera 5.0. For all other phones, you are getting build 14219 or 14226 of Windows Phone 8.1.1 with no significant new features or firmware.
Having said that, if you do have a Lumia 830, Lumia 930, or Lumia 1520, Camera 5.0 will blow you away and take our word for it, it is worth the torturous wait.
There's still no word from AT&T or T-Mobile about their Denim updates. We do know the carriers are testing it, but so far, no ETA is on the table to our knowledge. A "by the end of the month" estimate is certainly not out of the question though, even for them.
Source: Microsoft India (Twitter); Thanks, Sarang D. and Kumar C., for the tip!