Minecraft wiki entry for Caves_%26_Cliffs, associated text: On Java Edition, Part I started development with snapshot 20w45a, which was released on November 4, 2020. The first pre-release for Caves & Cliffs: Part I was released on May 27, 2021, and the first release candidate on June 4, 2021. Part II started development with 1.18 Experimental Snapshot 1, which was released on July 13, 2021, followed by the first pre-release on November 11, 2021, and the first release candidate on November 25, 2021.