Android Timeline [Infographic]

he Android OS was first released in September 2008. Google rolls out new versions of Android on a frequent basis, but has no set time for each future version. Some of the in-between versions were never released commercially.
It typically takes manufacturers 6 to 12 months after a specific Android Software Development Kit (SDK) release to deliver products using that version, so the vendor can complete custom additions, interface code and QA the device. Although not supported by manufacturers, it is often possible to install a newer OS version into a 'rooted' device.