I live in Orlando, FL. I am breaking my lease, the lease has a early termination clause, that the land is not willing to honor, claiming a new state law, which they claim gives them the right to override the lease I signed. Can the landlord do this legally without first notifying the tenants in writing of the change?

Ask the landlord to give you the cite (code section) for this alleged new law. Generally laws like that take effect only in the future, they don't affect past contracts. So I think your landlord is BSing you.

If he can't give you the cite for this law so you can look it up yourself, tell him that you don't believe such a law exists and you expect him to abide by the terms of the lease. By the way don't use the term "breaking the lease" that's not what you are doing, you are exercising the early termination clause provided for in the lease.