Cross validations rule restricts user to enter invalid code combinations in the system.When we apply new CV rules in the system we know that it will not going to affect the existing code combinations so my query is that lets say we are entering an invoice using a code combination as we know that new CVR will not affect the existing combinations and the combination I am using while entering an invoice in the system is an invalid combination according to the new cross validation rules but it is a valid combination according to the previous rules.So will system restrict the user if I will use that combination which is an invalid according to the new rules?

Please reply me urgently as it is creating some confusion.