> 2013. Did they say anything back then about future upgrade-ability?
By 2013 they had completely dumped all Windows Mobile 6.x users with no upgrade path, not even for apps or even the development tools. They had also dumped all Windows Phone 7 as none would go to WP8. Fanboys (as the one above) claimed that 7.8 would (or did) give all WP8 features but all it gave was a few extra colours and a couple of new sizes for the UI tiles.
I would be surprised if anyone expected upgrade-ability for a WP8 phone, but it seems that some will upgrade to 10 - probably whether the user wants to or not.
None will get continuum, that requires dual GPUs or something and is only on 950s.