In order to be able to enjoy Windows Phone 8.1 Update 2 you need to be rocking either the Lumia 640 or the Lumia 640 XL as these are the only Windows Phones with access to that particular release. Microsoft today shared details on Update 2 during a Q&A session at the UK launch of these two smartphones, stating that the update will come to select devices in certain markets.
The company did note that both the Lumia 735 and Lumia 830 would receive Update 2. It's not known when or where the update will be rolling out, not to mention which handsets will receive that version of Windows Phone 8.1. All we know is the update is planned for some Lumia 735 and Lumia 830 handsets.
The remote kill-switch laws were highlighted in the response during the session, which signifies the possibility that Windows Phones in the US will receive Update 2. Though again, it's not known as to which networks would roll out the update or if any Windows Phones aside from the Lumia 735, 830 and 640 would receive Update 2.
We'll hopefully have more details in the near future.