You do have control over them because, indeed, you have the private keys (and the NSA too, reminds me of the Facebook setting "only me+NSA" (only three quarters joking)). You want to run v2 domains? Go ahead, but the people that want to visit your legacy addresses must use the legacy software. It seems like an inherent risk with software-controlled domains that the (old) software (version) might not be used anymore.