Must?
No not if things go as they have been. Without doing anything the new content may only appear in unexplored ares. But I always draw folks attention to a nice mod called upgrade world that resets biomes and the good thing is: once you have used it you don't have to run with it permanently.
Basically I have used it a couple of times ot reset the same world with the tar pit then Ice cave updates no issues.

Originally posted by Zathabar:

Must?
No not if things go as they have been. Without doing anything the new content may only appear in unexplored ares. But I always draw folks attention to a nice mod called upgrade world that resets biomes and the good thing is: once you have used it you don't have to run with it permanently.
Basically I have used it a couple of times ot reset the same world with the tar pit then Ice cave updates no issues.

But the buildings will be removed with this mod??

By default No. It scans for player structures in a radius and if found does not upgrade that area. You can make it very mercenary and upgrade everything which may damage o remove builds but not by default: The Mod Author JereKuusela thought of that :)
Upgrade_World by JereKuusela
Download your Servers database locally and try it to avoid any possibility of smashing your hard work. If it then works re upload the adjusted db. Thats what I did.

Originally posted by Zathabar:

By default No. It scans for player structures in a radius and if found does not upgrade that area. You can make it very mercenary and upgrade everything which may damage o remove builds but not by default: The Mod Author JereKuusela thought of that :)
Upgrade_World by JereKuusela
Download your Servers database locally and try it to avoid any possibility of smashing your hard work. If it then works re upload the adjusted db. Thats what I did.

Thanks we will try the mod :D