Convert maps to new update version ?

My server map was created in 1.3.2, how do I convert it to 1.4.2 ?
So that the new stuff populates the map ?

Sorry if its a dumb question

 

New blocks and structures, for example witch huts, will be generated in new chunks. Old, existing chunks of your 1.3.2 map will not change. Entities usually don't care whether a chunk is old or new, so for example slimes will probably spawn in both old and new swamp biomes.

 

All new chunks will load with the new stuff. But if you current chunks to be reloaded then get a plgion wht does that, but it will mess up with your world (chunk errors, new world gen) - http://img97.imageshack.us/img97/7338/20111221173542.png (http://www.minecraftforum.net/topic/885723-chunk-error-awesome-mountain-overhang-seed/)

 

Ok good to hear, my servers map is failry new so there is plenty of room for new chuck generation.

Thanks