Let's give some information about the update and talk about innovations: Minecraft's cave and mountain forms will get a different look for the first time in years by receiving an update that will change the center of the game. For this reason, the name of the update is the Minecraft 1.17 Caves and Mountains Update. The release date of the full version was announced as the summer of 2021.
I have listed below the contents that I detected from the broadcast and stated to be added.
For the mountains: Goats will be added. The snow will be denser than before. (Snowier Snow XD) Snow powder will be added. The formation of the mountains will be completely new.
For caves: The Warden monster will be added. Lush caves will be added. The deep dark biome will be added. Damlata caves will be added. The composition of the mines has been completely updated and they will become larger. Amethyst crystal will be added. Candles Will Be Added. Copper mine will be added. Copper blocks will be added and the physics of rusting will also be included. and more will be announced over time
Other Content to be Added; Axolotl will be added. Glow Squid Will Be Added. Archeology Will Be Added. A telescope will be added. Lightning rod will be added. The sack will be added. Brush will be added. Wireless Redstone will be added. and more will be announced over time