Island Adventures - Core is a shared mod between our Shipwrecked and future Hamlet mod. Core's purpose is to store all the shared assets that are used in both DLCs (ex: items, characters, mechanics, sounds, and way way more!)
GemCore's features that IA relied on in the past have since been incorporated into the game itself. The only feature we still used prior to our newest update was the system for Alt Recipes, which has since been replaced with a world-based crafting system; so the items that need a modified crafting recipe will have one set recipe depending on if you're in a DST, SW, or Ham world.
Yes! If you'd like to include IA-Core in your game you can enjoy features such as the SW Characters, SW Boats, some SW craftables, SW/Ham Crops, the Palm Tree Oasis, and more!