Android has been often criticized for the time it takes for OEMs to release the latest versions of the mobile OS to customers, but HTC has put up an useful infographic in which it shows us how updates are released for carrier devices, unlocked edition and developer devices and Google Play edition (GPe) devices.

According to HTC, there are several steps involved in releasing an Android update, as follows:

• Stage Zero: Evaluation
• Stage One: Development
• Stage Two: Integration
• Stage Three: Test/Certification
• Stage Four: Push to Customer

Stage Zero: Evaluation

As you’ll notice in the detailed image (link at the end of the post,) it all starts with Google releasing the PDK to OEMs (HTC included) ahead of the actual announcement of an upcoming version of Android, so the new framework can be evaluated. After the new version of Android is released, OEMs further evaluates requirements, while waiting for the chipset manufacturer to determine whether the new Android OS version will be compatible with its current chips.

Stage One: Development

Then, drivers and optimizations are released by the chipset maker for the chips that will support the new Android OS version, with a “modified board support package (BSP)” being delivered to HTC for the devices that use the chipset.

Stage Two: Integration

Up until now, no matter what HTC device we’d be talking about, HTC proceeds in a similar fashion. However, after the BSP is provided, HTC takes different steps depending on the device it has to update. On GPe devices, HTC moves directly to testing, while on carrier and unlocked models, HTC comes up with a new software version for those devices to asses whether it can support them – in case the devices are supported then the source code is infused with HTC’s Sense for each device. For carrier versions, the company has an additional step in place after integrating Sense, which is working with each carrier to add carrier modifications including apps, services and requirements to the firmware.

Stage Three: Test/Certification

The next step is for HTC to submit a software build for Lab Entry, which is then tested. In case bugs are found during testing, a new build with fixes is released. The carrier versions of the handset will be tested by carriers as well, which have to approve the update before it can be released to the public.

Stage Four: Push to Customer

Once the software is accepted, Google Issues its Technical Acceptance, at which point HTC prepares the over-the-air (OTA) update to be released to customers. HTC handles the update for the unlocked and developer edition versions, Google pushes the update to GPe models, while HTC and carriers release the update for the carrier versions.

Wrap Up

The infographic shows there are eight and nine steps for GPe and unlocked devices, respectively, to be updated, while carrier updates require 12 steps – that’s why carrier updates take longer to be released (image above). Considering that most people buy on-contract handsets – therefore carrier custom models – the infographic explains why they’ll have to wait longer to run the latest Android OS version in town. While this is an infographic provided by HTC for HTC devices, other OEMs most likely have similar Android update steps in place for their devices.

In addition to providing the infographic, HTC has listed the Android 4.4 KitKat update status for various HTC One versions:

• Unlocked HTC One – update complete
• Developer Edition – update complete
• Google Edition – update complete
• AT&T HTC One – Integration (step two)
• Sprint HTC One – Integration (step two)
• T-Mobile HTC One – Integration (step two)
• Verizon HTC One – Integration (step two)

Are you already running KitKat on your HTC device?

Click here to see the detailed infographic.