Java Edition 1.17

1.17, the first release of the Caves & Cliffs update, is an upcoming major update to set to release in mid-2021. It was first announced during Minecraft Live 2020 on October 3, 2020.

Blocks

 * Amethyst Bud
 * Grows from budding amethyst, which is found in amethyst geodes.
 * Starts out small, but grows into medium after a while, large after even more time and eventually becomes an amethyst cluster.
 * Unlike crops, each growth stage is a separate block instead of a block state.
 * Drops only when mined with a Silk Touch pickaxe.


 * Amethyst Cluster
 * The final, mature stage of the amethyst bud, which grows from budding amethyst in amethyst geodes.
 * Drops amethyst shards if broken, in an amount affected by Fortune, but can also be picked up with Silk Touch.
 * Emits a light level of 5.


 * Azalea
 * Bush-like block which can be planted on dirt and grass blocks.
 * Azalea can grow from moss blocks when bone meal is used on them.


 * Azalea Leaves
 * Has variants with either no blossoms or pink blossoms.
 * Yield azalea bushes and sticks on decay.


 * Block of Amethyst
 * A block found in amethyst geodes.
 * Unlike the Budding Amethyst, the Block of Amethyst can be obtained when mined.
 * Can also be crafted with 4 amethyst shards.


 * Block of Copper
 * Can be crafted with 4 copper ingots, and can also be crafted back into 4 copper ingots.
 * Oxidizes and changes texture to a turquoise-green over time.
 * Can be stopped from oxidizing by combining it with a honeycomb to create a Waxed Block of Copper.
 * Can be crafted into cut copper.


 * Budding Amethyst
 * Generates amethyst buds/clusters on any side that is exposed either to air or a water source block.
 * Cannot be obtained when mined, even with Silk Touch, and does not drop anything.
 * Breaks immediately if pushed by a piston or sticky piston.
 * Cannot be pulled by sticky pistons.
 * Generates in amethyst geodes.


 * Calcite
 * An off-white stone that generates in geodes, between tuff and amethyst.


 * Candle
 * Crafted with honeycomb and string.
 * Comes with 16 dyed types and a yellowish non-dyed type.
 * Can be lit by any item that produces fire.
 * Up to 4 can be placed in a single block, similar to sea pickles, for a maximum light level of 12.
 * Only candles of the same color can be placed on the same block.
 * Only one can be placed on an uneaten cake and lit.
 * If any of the cake is consumed, the candle pops off.
 * Can be placed underwater, but cannot be lit.


 * Cave Vines
 * A natural light source, with a light level of 10.
 * Drop glow berries.
 * Growth can be sped up using bone meal.
 * Berries can be harvested by with the vine.
 * Grow from glow berries when placed on the underside of a block.
 * Unlike regular vines, they cannot be climbed.


 * Copper Ore
 * Generates randomly underground in small veins, but this has been confirmed to be a placeholder.
 * Has the same rarity as iron.
 * Generating starts at the same minimum level(s) as iron.
 * Can be smelted into a copper ingot.


 * Cut Copper
 * Can be made into stair and slab variants.
 * Oxidizes and changes texture over time.
 * Can be stopped from oxidizing by combining it with a honeycomb to create Waxed Cut Copper.


 * Cut Copper Slab
 * Oxidizes and changes texture over time.
 * Can be stopped from oxidizing by combining it with a honeycomb to create a Waxed Cut Copper Slab.


 * Cut Copper Stairs
 * Oxidizes and changes texture over time.
 * Can be stopped from oxidizing by combining it with a honeycomb to create Waxed Cut Copper Stairs.


 * Dripleaf
 * Allows an entity to stay on it for 1.5 seconds (30 ticks), before the entity will fall through it.
 * The tilt happens in 3 stages: Unstable, Partial, and Full. These can be seen in the F3 debug menu.
 * All the stages are solid except the Full stage, which is when the player falls through.
 * When nobody is standing on it, it is set to None stage.
 * If the player sneaks on it while it's in the Unstable stage, it will return to None. Sneaking on it while it's in Partial or Full stage has no effect.
 * Comes in two sizes: Small and Big. Small can be applied bone meal to grow into Big.
 * Small Dripleaf can only be obtained with shears (otherwise breaks), and can only be planted on clay, or underwater on clay and dirt blocks.
 * Big Dripleaf can be obtained with any tool or by hand, as well as breaking it using projectiles, and can be planted on grass and dirt blocks.


 * Dripstone Block
 * A decoration block.
 * Appears to be made of the same materials as stalactites and stalagmites but as a full cube.
 * Only generates in the Dripstone caves biome which is currently only available through single biome, caves, or floating islands world types.
 * Can be crafted from 4 pointed dripstone.


 * Flowering Azalea
 * A variant of the azalea with pink blossoms.


 * Glow Item Frame
 * Placeable entities which appear to glow.
 * Do not affect the light level, only appearing as if lit up themselves.
 * Items placed inside also glow.
 * Crafted using an item frame and a glow ink sac.
 * Includes application to maps.


 * Glow Lichen
 * A naturally occurring light source found rarely in caves, growing on any face of a block.
 * Has a light level of 7.
 * Obtained with shears, otherwise breaks.
 * Does not spread naturally, although bone meal can be used to spread it horizontally (or vertically if on the side of a block).
 * It spreads to adjacent spaces, up to 4.
 * Can be waterlogged.
 * Unlike vines, it does not pop off when underwater, and is not climbable.
 * Up to 6 can be put on the same block space, merging into one block.


 * Hanging Roots
 * Decorative blocks that can only be placed on the underside of a block.
 * Obtained with shears, otherwise breaks.


 * Lightning Rod
 * Can be crafted with 3 copper ingots.
 * Lightning strikes within a 32-block radius get redirected to the lightning rod.
 * Gives off a redstone signal with a strength of 15 if hit by lightning.
 * Can be activated directly by throwing a trident with Channeling at it during a thunderstorm, though this does not produce a redstone signal.


 * Moss Block
 * An opaque block with a grass-like texture on all sides.
 * Can be bonemealed to grow grass, tall grass, moss carpets and both types of azaleas on it and in its vicinity.
 * Breaks when pushed by a piston.


 * Moss Carpet
 * Same texture as the moss block, but one pixel thick.
 * Crafted with moss blocks.


 * Pointed Dripstone
 * Can be either placed on a ceiling to create a stalactite, or on top of a block to create a stalagmite.
 * Can be combined to form longer stalactites and stalagmites.
 * Thrown tridents break pointed dripstone. Will also break when pushed directly or with a block by a piston.
 * Stalagmites break if not attached to something below
 * Stalagmites hurt entities which fall on top of them more than normal fall damage.
 * Damage is relative to height: For example, jumping on a stalagmite deals of damage, and falling from 3 blocks deals  of damage.
 * Stalactites can fall or break if unsupported, and break apart on impact, hurting entities they fall on.
 * Damage is relative to height: For example, one falling from 2 blocks deals of damage, and one falling from 3 blocks deal  of damage.
 * They drip water or lava into cauldrons if a source block is placed above the stalactite, and gradually fill the cauldron. Water drips even without any water above the block (lava in the Nether), but does not fill the cauldron.


 * Powder Snow
 * A variant of snow, Entities that walk over it will sink into it.
 * Leather boots can be worn to prevent entities from sinking into powder snow blocks.
 * Players can still crouch to descend with leather boots. Wearing leather boots also allows powder snow to be "climbed", like water or scaffolding.
 * When inside a powder snow block, a frosty vignette appears around the player's screen and any entity inside starts freezing and taking damage after a short time.
 * Wearing any piece of leather armor will stop the freeze effect.
 * Can be collected and placed with a bucket.


 * Rooted Dirt
 * Decorative blocks.
 * A dirt-like block with roots on its texture.
 * Similar to coarse dirt, neither mycelium nor grass spread to it.


 * Sculk Sensor
 * A redstone component that detects vibrations.
 * Currently, it does not generate naturally, only available from the Creative inventory or commands such as, but natural generation is planned for future versions.
 * Senses vibrations such as block placement, footsteps, and projectiles, and emits a redstone signal.
 * Particle of the Vibration.gif Emits particles when it senses a vibration nearby.
 * A comparator connected to it will emit different signal strengths based on what caused the signal.
 * Does not detect ambient weather such as rain.
 * Wool blocks between the sensor and the cause of the sound prevent the sensor from detecting the sound.


 * Spore Blossom
 * Can only be placed on the underside of a block.
 * Sends green particles downward when opened.


 * Tinted Glass
 * A black variant of glass that is transparent to players, but does not let light through.
 * Can be crafted with 4 amethyst shards and a glass block.
 * Stained glass cannot be used to craft tinted glass.
 * Drops itself if mined without Silk Touch or even by hand, unlike glass.


 * Tuff
 * A grayish stone that composes the outer layer of amethyst geodes.
 * Texture may be subject to change.

Items

 * Amethyst Shard
 * Obtained from breaking amethyst clusters.
 * The amount dropped can be increased with the Fortune enchantment.
 * Can be used to craft tinted glass, blocks of amethyst and a spyglass.


 * Bucket of Axolotl
 * Obtained by using a water bucket on an axolotl, similar to fish.
 * Can be used to carry around and empty out axolotls, also similarly to fish.


 * Bundle
 * Crafted with 2 string and 6 rabbit hide.
 * Used to store other items (except shulker boxes) inside of it.
 * Can only hold a stack of items, but is able to hold different types of items inside of it.
 * Items with smaller stacks, such as ender pearls, take up more room in a bundle, and non-stackable items take up the whole bundle.
 * The bundle's contents can be opened by pressing while holding it, throwing out its entire content into the world. When destroyed as an entity, it drops the items it currently has as well.
 * Right-clicking a bundle in the inventory empties one item from the bundle.
 * The player receives a tutorial when first having a bundle in the inventory.
 * Even though bundles are not stackable, bundles can be nested.
 * Can hold up to 16 bundles.
 * Only empty bundles can be placed in other bundles without using commands.
 * Has a GUI when hovering over it.
 * Shows contained items in its GUI's inventory slots when hovering over it, as well as fullness as a number.
 * Note: Bundles can hold any amount of any item if added using commands.


 * Copper Ingot
 * Obtained by smelting copper ore.
 * Used to craft copper blocks, lightning rods and spyglasses.


 * Glow Berries
 * Can be eaten, restoring.
 * Grow on cave vines.


 * Glow Ink Sac
 * Dropped by glow squids when killed.
 * Can be used to craft glow item frames.
 * Can be used to make text glow on signs.


 * Powder Snow Bucket
 * Obtained by using a bucket on powder snow.
 * Can be used to place a powder snow block wherever it is used, or can be used to fill cauldrons with powder snow.


 * Spawn eggs
 * Added Axolotl spawn eggs.
 * Added Glow Squid spawn eggs.


 * Spyglass
 * Crafted with 2 copper ingots and an amethyst shard.
 * When used, it zooms in on wherever the player is looking, but limits their view to a square.
 * The scope texture is a glass square with a copper border.
 * The overlay that limits the view can be removed with a resource pack or by pressing.
 * There is a unique animation for using the spyglass, which is visible in third person perspective or by another player.

Mobs

 * Based on the Mexican salamander with the same name in real life.
 * Doesn't spawn naturally yet, must be spawned in with a spawn egg.
 * The first amphibian added to Minecraft.
 * Will dry out and start taking damage after 5 minutes of being out of water.
 * Can be caught using a water bucket, like fish.
 * Can be bred using tropical fish or buckets of tropical fish.
 * Come in five different colors (leucistic, yellow, brown, white, and purple/pink, and a rare blue Axolotl).
 * Blue axolotls are very rare, with a $1/1200$ chance of spawning.
 * Plays dead when damaged, receiving Regeneration I.
 * This regeneration ability is likely based on how real axolotls can regrow lost limbs.
 * Attacks drowned, guardians, squids, glow squids and fish, damage not yet official.
 * Are always hostile to fish and squid, and hostile to drowned and guardians only when "tempted" by a player holding tropical fish.
 * Are always hostile to fish and squid, and hostile to drowned and guardians only when "tempted" by a player holding tropical fish.


 * Originates from the mob with the same name from Minecraft Earth.
 * Underwater mob that behaves like a regular squid.
 * Does not naturally spawn yet.
 * Is attacked by axolotls without provocation.
 * Drops glow ink sacs when killed.
 * Does not affect the light level, only appearing as if lit up itself. Glows in the same way that magma cube cores, vexes, blazes and the eyes of spiders, drowned, and endermen do.
 * Stops glowing for a short time and swims away fast after taking damage.
 * Stops glowing for a short time and swims away fast after taking damage.

World generation

 * Amethyst Geodes
 * A new feature found uncommonly underground (can rarely appear exposed to the surface close to sea level).
 * Contains blocks of amethyst and budding amethyst blocks, which are encased in a shell of calcite and tuff.
 * Also generates with a small air pocket nearby which may open into the geode.
 * Generally generates at or below sea level (y = 63).
 * Most commonly generates at lower levels (y = 0 to y = 40)
 * Overrides standard caves and ravines, but is overridden by abandoned mineshafts.
 * Currently has a high generation rate, presumably for testing purposes which was also done with ruined portals before.


 * Dripstone Caves
 * A new underground biome, consisting of a massive cave biome containing vast quantities of stalactites and stalagmites.
 * Made up of primarily dripstone blocks and stone, with large clusters of dripstone blocks hanging from the ceiling, pointed dripstone on the floor and ceiling and many pools of water.
 * Does not yet generate naturally in normal worlds, and can only be generated using buffet worlds with "Dripstone Caves" selected as the source biome or using custom world. Natural generation is planned for future versions.

Command format

 * Modifies the inventory of a block or entity.
 * This command has three forms:
 * – same as old
 * – modifies item (without copying).
 * {{cd|/item copy
 * Whether entities take damage from freezing inside of powder snow.
 * Controls what percentage of players must sleep to skip the night.
 * When set to 0 or a negative value, a single player is sufficient to skip the night, and night is skipped immediately without the falling asleep transition.
 * When set over 100, the night cannot be skipped.
 * Set to 100 by default.
 * When set over 100, the night cannot be skipped.
 * Set to 100 by default.

Gameplay

 * Death messages
 * Added 6 new death messages:
 * " froze to death".
 * " was frozen to death by ".
 * " was skewered by a falling stalactite"
 * " was skewered by a falling stalactite whilst fighting "
 * " was impaled on a stalagmite"
 * " was impaled on a stalagmite whilst fighting ".


 * Loot tables
 * New condition:
 * Checks range of value.
 * Parameters:
 * – see "New value providers" section (currently combination of random generators and score)
 * – min/max range
 * New functions:
 * Modifies enchantments on item.
 * Parameters:
 * – map of enchantment id to level value (can be score or random number)
 * – if, change will be relative to current level. If , level will be replaced with current value (default behavior)
 * Sets tags needed for banner patterns. Parameters:
 * - list of pattern objects:
 * - name of pattern (square_bottom_left, bricks, etc.)
 * - name of color (light_gray, etc.)
 * - if true, new elements will be appended to existing ones instead of replacing
 * New value providers:
 * Returns scaled scoreboard value.
 * Parameters:
 * – scoreboard name
 * – same as in  predicate
 * – scaling factor (float)
 * – same as in  predicate
 * – scaling factor (float)

General

 * Particles
 * Added 7 new particle types:, , , , , and.


 * Tags
 * Added the entity type tag.
 * Contains tropical fish, pufferfish, salmon, cod, squid and glow squid.
 * Axolotls are always hostile towards entities in this tag.
 * Added the entity type tag.
 * Contains drowned and guardians.
 * Axolotls are hostile towards entities in this tag if they have been tempted.
 * Added the item tag.
 * Contains the tropical fish item and bucket of tropical fish.
 * Items in this tag can be used to tempt axolotls.
 * Added the block tag.
 * Contains the #flowers block tag, the #leaves block tag, grass, ferns, sweet berry bushes, and small dripleaf plants.
 * Added the block tag.
 * Contains all 17 types of candle cake.
 * If the player puts a candle on a cake, and keeps clicking the candle on the cake, the candle will be duplicated.
 * Blocks in this tag are considered candle cakes and can be lit, if they have the block states set to false.
 * Added the block and item tags.
 * Contains all 17 types of candles.
 * Blocks in this tag are considered candles and can be lit, if they have the block states and both are false.
 * Cakes use this tag to determine if a candle item can be placed on it or not.
 * Added the block tag.
 * Contains cauldrons, water cauldrons, lava cauldrons and powder snow cauldrons.
 * This tag is used in certain pathfinding processes.
 * Added the block tag.
 * Contains the cave vines body block and cave vines head block.
 * Added the block tag.
 * Contains amethyst blocks and budding amethyst.
 * Blocks in this tag play the "amethyst block chime" sound repeatedly for a short amount of time after being stepped on, gradually decreasing in volume.
 * Added the block tag.
 * Contains the block tag and dirt.
 * Used in dripstone generation to determine what dripstone can replace and what pointed dripstone can generate on.
 * Added the item tag.
 * Contains sweet berries and glow berries.
 * Added the item tag.
 * Contains leather boots, leather pants, leather tunic, and leather cap.
 * Having an item in this tag in an armor slot prevents players from freezing.
 * Added new tag type.
 * Added the item tag.
 * Contains leather.
 * Baby piglins do not attempt to pick up items in this tag. Adult piglins are unaffected. Baby piglins still follow the other rules adult piglins follow.
 * If an item is in this tag while simultaneously being recognized as a wanted item by piglins, this tag takes precedence.
 * Added the game event tag.
 * Contains the step, swim, falling, and shooting projectile events.
 * Game events in this tag will be ignored by sculk sensors if the source entity is sneaking.
 * Added the block tag.
 * Contains snow and powder snow.
 * Blocks in this tag will create snow stepping noises while the player walks in them.
 * Added the block tag.
 * Contains the #base_stone_overworld block tag, the #cave_vines block tag, dirt, gravel, sand, moss block, the #flowers block tag, grass, tall grass, moss carpet, small driplead, big dripleaf, big dripleaf stem, and vines.
 * Added the block and item tag.
 * Contains the block and item tag.
 * Blocks in this tag will prevent sculk sensors from hearing vibrations if the block is between the sculk sensor and the vibration.
 * As thrown entities, items in this tag do not trigger vibrations.
 * Added the item tag.
 * Contains raw and cooked porkchop.
 * Piglins can eat items in this tag.
 * Eating refers to the piglin seeking out and picking up an item without appearing in its inventory, thus vanishing.
 * Added the entity tag.
 * Contains foxes, rabbits, endermites, and silverfish.
 * Entities in this tag can walk on top of powder snow.
 * Added the game event tag.
 * Contains every game event.
 * Game events in this tag will trigger sculk sensors.


 * Textures
 * Added a block texture named.
 * This texture is unused in-game.

Blocks

 * Banners
 * The unused "base" pattern has been renamed to the "field" pattern and given proper translation strings (its ID is still "base").


 * Cakes
 * Have a variation called "Candle Cake".
 * Can be created by using a candle on an uneaten cake.
 * The candle on the cake comes with 17 colors, depending on the color of the candle used to create it.
 * The candle will pop off when any of the cake is eaten.


 * Cauldrons
 * Can now be filled with lava and powder snow.
 * Lava filled cauldrons can damage players and mobs inside of them, and give off a redstone comparator signal of strength 1.
 * Powder snow cauldrons are formed when cauldrons are under the sky during snowfall.
 * Can also be filled with powder snow by a powder snow bucket on it.
 * Have been split into normal, water, lava, and powdered snow cauldrons.


 * Composter
 * Some items are now compostable:
 * 30% chance: non-flowering azalea leaves, glow berries, moss carpet, small dripleaf, hanging roots.
 * 50% chance: flowering azalea leaves.
 * 65% chance: spore blossoms, non-flowering azalea, moss blocks, big dripleaf.
 * 85% chance: flowering azalea.


 * Dispenser
 * Can now place powder snow using a powder snow bucket.
 * Also can remove it using a bucket.


 * Grass Path
 * Renamed to "Dirt Path", as per Bedrock Edition.
 * The block ID has also been changed to.
 * Can now be made with dirt, coarse dirt, mycelium, and podzol by using a shovel.


 * Lapis lazuli block
 * Renamed to "Block of Lapis Lazuli".


 * Pistons
 * Particles now appear if a block is broken by a piston.
 * Sounds, however, do not play.
 * Breaks Budding Amethyst if pushed/pulled with a piston/sticky piston.


 * Rails
 * Are now able to be waterlogged.
 * No longer break when contacted by water.


 * Signs
 * Can now be tinted with glow ink sacs to make the text glow.
 * Glowing signs do not affect the light level, only appearing as if the text itself is illuminated.
 * A new  block state had been added to indicate whether the sign text is lit up.
 * Regular ink sacs can be used to remove the glowing effect.
 * Now has sounds for being dyed.


 * Stonecutter
 * Can be used to craft the different copper block variants.


 * Structure block
 * Default mode of structure blocks is now "Load". "Data" is now hidden by default.
 * "Data" can be accessed by clicking the mode button while holding the key.


 * Water
 * Flowing water no longer breaks rails.

Items

 * Clock
 * The texture has been changed from Clock JE2 BE2.gif to Clock JE3.gif.


 * Compass and Lodestone Compass
 * The texture has been changed from Compass JE2 BE1.gif to Compass JE3.gif.


 * Firework Rockets
 * Simple firework rockets with one gunpowder can now be crafted using the recipe book.


 * Pufferfish
 * The strength of the poison effect has been decreased from IV to II.


 * Shulker boxes
 * They now drop their items when destroyed as entities.

Mobs

 * Drowned
 * Now have a chance of dropping a copper ingot instead of a gold ingot.


 * Foxes
 * Eat glow berries.


 * Shulkers
 * If a shulker is hit by another shulker's projectile, it now has a chance of spawning a new shulker. Shulkers are more likely to spawn new shulkers when there are fewer shulkers nearby.


 * Skeletons
 * Begin the process of turning into strays when they are inside powder snow after 30 second and finally turn into strays after 45 second.


 * Wandering Traders
 * May now sell Small Dripleaf.

Non-mob entities

 * Experience Orbs
 * Will now sometimes merge when in large quantities, to improve performance.
 * Merging will not affect the amount of experience gathered from collecting the merged orbs.
 * No longer follow dead players.


 * Minecarts
 * Can now move in water, but move considerably slower than they do on land.

World generation

 * Biomes
 * Biome-specific sky colors now blend more smoothly.

Command format

 * Removed command.
 * Replaced with.
 * Replaced with.

Gameplay

 * Absorption effect
 * The yellow absorption hearts will now stay yellow if the player has the Poison or Wither effects, instead of appearing empty.


 * Advancements
 * Glow berries are now required for A Balanced Diet.


 * Loot tables
 * Loot tables can now access scoreboard values by UUID.
 * Loot table values inside random number generators can now be nested.
 * Changed condition:
 * parameter has now been replaced with . It can either contain value from old field (like ) or be an score holder name in form.
 * Changed function:
 * This function now has parameter. If, change will be relative to current damage. If , damage will be replaced with current value (default behavior)
 * Changed function:
 * This function now has parameter. If, change will be relative to current item count. If , item count will be replaced with current value (default behavior)
 * Changed function:
 * parameter can now be set to, to access command storage.


 * NBT data
 * All projectile entity data now has a field called HasBeenShot.
 * If this field is false, during the next tick the projectile will fire a projectile shot game event, causing any nearby sculk sensors to react.


 * Recipe Book
 * Some recipe-unlocking advancements had criteria names changed.
 * The chiseled nether bricks recipe is now unlocked by having a nether brick slab instead of a nether bricks block.
 * The chiseled polished blackstone crafting recipe is now unlocked by having a polished blackstone slab, instead of polished blackstone.


 * Snowfall
 * During snowfall, cauldrons under the sky now slowly fills with powder snow.


 * Subtitles
 * Changed  to.
 * Changed  to.

General

 * Block Models
 * Made the vine's block model much simpler.


 * Custom dimensions
 * Added height and min_y variables to dimension types, allowing for the height limit to be increased in custom worlds settings.


 * Data and Resource Packs
 * Changed the  number in   from 6 to 7.
 * Changed the resource pack version number from 6 to 7, as the following have been changed:
 * Drowned texture mirroring has changed.
 * Slots for the game mode selector are now 26 pixels instead of 25.
 * Data pack version is also changed to 7.


 * Dedicated servers
 * A dedicated server can enforce custom resource packs by setting in . When this option is used, players will be prompted for a response and will be disconnected if they decline the required pack.


 * Entity storage
 * Entities have been extracted from main (terrain) chunks and are now stored in separate directory (similar to POI storage). Those new files are still region files with NBT.


 * Languages
 * Removed the Gothic, Kabyle, Maori, Mohawk, Nuk, Ojibwe, and Talossan languages as their translations were incomplete.


 * Libraries
 * The game now uses javabridge 1.1.23 instead of 1.0.22.


 * Menu screen
 * Buttons tied to a set of values can now be scrolled through.
 * Clicking on a menu button changes it to the previous value.
 * The debug mode can now only be accessed by holding instead of  while clicking on the world type button.


 * Obfuscation map
 * Changed the license included in the obfuscation map.


 * Resource packs
 * Improved performance when using many overrides on an item model.
 * toasts.png gui texture has a new icon for the bundle tutorial.


 * Servers
 * Removed the server setting.
 * Changed the error message for failing to connect to the authentication servers. Now says they are "not reachable" instead of "down for maintenance".


 * Tags
 * Added azalea leaves and azalea leaves flowers to the block and item tags.


 * Translation strings
 * The "World Type" string no longer contains a colon (":"). The colon is still visible in-game, however.
 * Changed "Use VSync" to "VSync".
 * Removed the unused string for enabling VBOs, "Use VBOs".
 * Added strings, "Mode", "Type", "Triggering", and "Track output". These are read out by the narrator for buttons in the command block UI.


 * World Selection
 * Added unique warnings for downgrading a world.

World generation

 * Underground Cabin
 * Seen in the Deep Dark biome during the Minecraft Live 2020 stream.
 * Consists of a chamber with a cobblestone floor and stripped log support beams, containing 3 barrels, a blast furnace, and a large chest, with cobwebs and candles in and around it.
 * May possibly not be a generated structure, but instead a construction built for the purpose of the Warden showcase.

General

 * Height limit
 * May be increased. It is considered to change only in the overworld as stated by Jeb.
 * As of 20w49a. World-height related values are now exposed for customized worlds, which might confirm that height limit might get removed or increased.

Trivia

 * This is the first Java Edition update to add a new ore to the overworld since emerald ore was added in  in 2012.
 * Similarly, this is also the first Java Edition update to add a real-world metal into the game since Classic 0.0.14a in 2009, which brought both iron and gold.