Leaked Google Document: Smartphone Manufacturers will be forced to provide the latest version of Android, i.e. version 4.4 KitKat installed in the new handsets, under Google’s new policy. Google will no longer approve GMS distribution of new Android products that ship older platform releases. The new policy will be applied on newly newly manufactured Smartphone Handsets only. The reports claim that Google thinks that it is useless to launch new Smartphones of Smartphones in the market withinstalled on it, unless you are not bringing the new device with the latest and greatest version from the Android team.
Source: https://thehackernews.com/2014/02/Google-Force-latest-Kitkat-Android-version.html