updates - What is Google's OTA phase deployment strategy?

I have always wonder what is Google's deployment strategy for OTA for latest software updates.
I do know that they do it in phases but, do they do it base on time zone? model's serial numbers? In other words how do they pick who gets it first or not. I have a 2013 Nexus 7 and it has been about 2 weeks since the release of Kit Kat 4.4 and I have not received it yet.

Answer

It appears to be random chance.

In this reddit thread, Google Employee Dan Merrill says of OS update rollouts and "mashing" the "check for updates button":

Rollouts are conducted in phases. Typically they start at 1% of devices for around 24 - 48 hours; we watch the return rates and resulting device checkins and error reports (if any), and make sure nothing looks wrong before sending it to more. Then typically it goes to 25%, 50%, 100% over the course of a week or two.

What the percentages mean is that when your device checks in, it has a 1% chance (for example) of being offered the OTA. If it doesn't (randomly) get an offer, it will never get an offer until the next batch.

IOW, once your device checks in and gets turned down, that's it until the next batch. Mashing on the "check for updates" button just causes your device to check in again, and get automatically turned down again. Think about how that makes your device feel! WON'T SOMEONE PLEASE THINK OF THE PHONES?!

That said, once the new batch does start, hitting that button does give you a new roll of the dice -- but once. Since devices usually only check in for system updates every 24 hours (I think? Certainly on a many-hours basis) this can get you your shot sooner than it would happen on its own.

So, mash away. :) Just be patient, and mashing on it more often than once or twice a day isn't going to gain you anything.

Edit: also, keep in mind that this isn't first-come/first-served. You're not racing other devices to get your slot in the current batch, or something.

He also warns against the "clear data on the Google Services framework" trick, as all that does is make the network think that it's dealing with a factory-reset device and makes you lose all the tokens used by apps that use it. It will not necessarily get you the update faster. (It might, but it might not.)

Source(s): Android and Me, Android Community

p.s. He also states in another message that if you're really impatient you should do an ADB sideload.