There are numerous steps the phone has to go through before it can be updated. First, Google needs to release the source code. That’s already done.


 

After that, the manufacturer of the device needs to decide if they should update the device. If it is a very popular device, it will get updated. Or, if it is a Nexus device, it will get updated for some time. About 2–3 years.

After the manufacturer decides to update it, it will then be built. The OS will then be sent to the carrier. If they decide to update it, then they will put all of the bloatware on the OS, and then send it out to the device. (Keep in mind, this only happens if you buy the device from a third party, like T-Mobile)

So, in short, the only way you can update the device, if it hasn’t been updated already, is to build the OS yourself, or find somebody who can, root it, and flash the new OS onto the device (I’d back it up before you do that, otherwise, if it doesn’t work, there may be no fixing it).

If your phone’s manufacturer updates the OS, you can easily check for and make updates. However some manufacturers don’t, but you can update the OS manually. Unlike the first option, this will clear all the data on your device, and you’ll need a laptop to do it.

The process involves first downloading the new version of Android that you’d like to install on your phone instead (called the Android ROM), and you can usually find the files you need online with pretty good tutorials. You’ll then have to flash the ROM on your phone, most likely using SP Flash tool, which will wipe your phone and install the new ROM. That’s usually how you get your phone back if you forget your password.

That being said, you can start by googling the available ROMs for your Android device and then following the instructions to flash.

Ways you can update your phone

  1. OTA update by your phone carrier
  2. ROMs : If updated stock ROM is available for download, you can flash it via your recovery. Check whether your phone has custom ROMs built.

I have to answer this in a detailed way.

Snapdragon 800 series and Snapdragon 600 series will get more updates than Exynos, Kirin and Mediatek processors.

The answer is that phone with the latest snapdragon processor.

And Among these snapdragon processors, 800 series is considered premium segment.

By the time of writing, Snapdragon 821 was recently released and are used in Google Pixel, LeEco Le Pro 3, Oneplus 3T, Xiaomi Mi 5s.

Snapdragon 820 is another premium segment processor released in the same year 2016. Eventually both will get updates for same period of time.

But the manufacturer’s dont roll out updates for more than 2.5 years.

Google Nexus series and Motorola are the two companies that released updates quickly for a longer period.

Now Oneplus will be the brand that will get longer period of update support as it is more popular among custom ROM developer Community.

Snapdragon 835 was released in CES 2017 and Galaxy S8 will be the first phone to feature it.

If you are aware of custom ROMs, then Oneplus should be your choice. The Oneplus 3T.

If you are a regular smartphone user, then Google phones, Oneplus, Xiaomi Mi series, Motorola Z series and Samsung S series should be your choice. Named in the order of priority.