Most likely Section 209 or 205. But I can't tell you when - not sure anyone except the powers that be, I am sure they have a formula of some type predicated on the number of lots still for sale, number of homes under construction etc. Also don't know which areas will be designer or cottage neighborhoods. If you go here
Sumter County - Geographic Information System you can see the sections that have the lots approved thus likely the next areas to be opened.