The first prerelease version of the upcoming update is out today, which means the first part of Caves & Cliffs will be available very soon. The developers added a lot of achievements related to new blocks and mobs, brought candles back to the game, and also made a number of other useful changes.
All changes in the Minecraft 1.17 Prerelease 1:
- added 11 achievements related to goats, axolotls, copper blocks and other items from the update;
 - candles were returned to the game, they received improved textures for the lit state;
 - text on glowing signs is now easier to read thanks to the outline;
 - azalea can now be planted in a flower pot;
 - fixed many bugs.