Sure. If you’ve agreed a support schedule upfront then by all means you should honour it. I’m not sure though that I’d be bad-mouthing my own products at the same time. Although actually thinking about it, I can’t see why you wouldn’t :)

Still, supporting from Microsoft’s point of view just means providing security fixes; they’re perfectly within their rights to stop making their new sites work with it (as evidenced by the new online Office that doesn’t work with it).