I thought the new law took effect October 1, but in any case it is NOT a "castle doctine" law. Florida already had a castle doctrine in effect.
The change in Florida, whenever it did or does become effective, is that OUTSIDE of your home you no longer have a "duty to retreat" before you can legitimately employ deadly/lethal force in self-defense. The old Florida law, like that of many other states, requires that EXCEPT WITHIN YOUR HOME you had to retreat from a threat if you could do so safely, and only if you could not safely retreat were you allowed to use deadly force in self-defense.
The new law removes the requirement to retreat as a prerequisite to the use of deadly force in self-defense. This has nothing to do with "castle doctrine," since the new law specifically addresses situations outside of and away from the home.