No, but it makes business sense to require users to buy a new dish anyway.

New dishes can make better use of limited frequency resources (eg. They support polarization). So they can squeeze more users in the same bandwidth if everyone has a new dish. So at some point, they'll require everyone purchase a new dish.

And fewer hardware versions to support is less burden on the engineering team.

That is part of why I think they should be providing the dish hardware for free as part of the service... The incentives are misaligned if the user buys the dish but spacex decides when it's deprecated.