It may be supported until 2021 but clearly new devices and apps/plugins wont! I used to use the OS getamap service in the uk which was excellent but only supports silverlight, so when I switched from windows laptop to chromebook I had to give it up, I spoke to os and they do not have any clear plans as I can see to move to html5 however I notice that on there site it mentions silverlight supported on 60 percent of internet platforms which has to be a concern for any company with such a product as this percentage is not going to increase!