Floating Islands was removed in the Caves & Cliffs update, this data pack brings it back. Simply add the data pack in the world creation screen, and generate your world. Although obvious, it is worth mentioning that this does not work with other data packs that modify world generation.
How to change biome
Like the original Floating Islands world type, the biome is fixed on plains.
You can change this by editing the overworld.json file in the data pack folder, and replacing "plains" with any biome name like "forest", "lush_caves", etc ...
Как запустить датапак Floating Islands на сервере?
Датапак Floating Islands удобнее всего раскрывается на общем сервере: установили один раз - и вся компания играет с новыми механиками. Создать сервер Майнкрафт с датапаком Floating Islands можно за пару минут вместе с BungeeHost.