Well it isn't officially announced yet but the page they accidentally published definitely said you had to pay £30 for a Superhub to get the upgrade.
Docsis 1 can support 38Mbps so they could do it that way but my interpretation was that they were requiring the Superhub because it would be provided on Docsis3 which I don't think the current non-50Mbps modems can support.
Time will tell.
Here is the leaked page in the google cache (it has been pulled from the site).
http://webcache.googleusercontent.com/search?q=cache...
If you can't fix it with a hammer you've got an electrical problem.