That feeling when the business wants you to allow massive chunks of data to simply be missing or not required for "grandfathered" accounts, but required for all new accounts.

Our company handles tens of thousands of accounts and at some point in the past during a major upgrade, it was decided that everyone prior to the upgrade just didn't need to fill in the new data.

Now we are doing another major upgrade that is somewhat near completion and we are only just now being told that we have to magically allow a large set of our accounts to NOT require all of this new required data. The circumstances are clear as mud. If the user changes something in their grandfathered account or adds something new, from that point on that piece of data is now required.
But everything else that isn't changed or added can still be blank...
But every new account has to have all the data required...

WHY?!