Low end Lumia 550, the 650 in the mid tier and 950/950 XL at the high end are all better devices than the windows phones that have come before them and are designed to run Windows 10, and so will be fully supported, as are devices such as the Lumia 830, Lumia 640 and 640 XL, BlU Win HD LTE and more. If you have one of those phones affected and want Windows 10 Mobile, the only option now is to buy a new device, maybe on ebay or auction sites or discount retailers if money is a reason you haven’t upgraded yet.
[Update 7/29: Microsoft has now officially blocked this route, pushing the Anniversary Update to the Release Preview ring, and removing support for the older devices.
