It's not a new law. If you have a lease agreement, your tenancy has a specific term and is governed by s.83.575, Fla. Stat.
Otherwise if you have no lease agreement and your tenancy is year-to-year (meaning you pay one year worth of rent all at the same time, and then pay again the next year) then you are owed a 60 day notice pursuant to s. 83.57 Fla. Stat.
Your tenancy length is defined (roughly) under s. 83.46 Fla. Stat.
If you have a lease then it governs in terms of notice periods. It is actually 60 days for a year to year but that is if there is no written lease; more of a fallback provision. Generally the lease governs. If the lease says 30 days then it is 30 days.
Both attorneys have given you excellent advice. If you need further assistance, you can use the Find A Lawyer function on the top of the page. Good luck!