Java Edition 1.17

1.17, the first release of an unknown update, is a major update to with no set release date. It revamps mountains and fixes bugs. It also revamps combat.

Gameplay
''Note:In this section, this assumes that Combat would be updated in 1.17, it is likely that it may be added in an update such as 1.18.
 * Attributes
 * Enchantments
 * Cleaving.
 * Shields
 * New shield indicator.
 * Sneaking, by default, automatically activates the shield.
 * Sneaking, by default, automatically activates the shield.

Blocks and Items
Note:The features below were stated to be added in a later update, however, even though it's been a long time, these biomes still may not be updated in 1.17.
 * Snowier Snow
 * Players can sometimes sink into the block.
 * Snowy Stone
 * Snow on top of stone gives the stone a different texture, like the Grass Block.
 * New Stone Variants?
 * Looking closely at the video and you see 3 stone textures, the original, the one at the surface, also the snowy stone texture, texture similar to gravel and the final one, a deepstone, texture similar to blackstone.
 * Palm Logs
 * Can be crafted into Wood, Planks, and all the other things that overworld wood can craft.
 * Palm Leaves
 * Spawn in Palm Trees
 * Baobab Logs
 * Can be crafted into Wood, Planks, and all the other things that overworld wood can craft.
 * Are 2x2.
 * Home to the termites.
 * Baobab Leaves
 * Spawn in Baobab Trees

Mobs

 * Goats
 * Spawn in mountain biomes.
 * Flee from players.
 * Termites and Ostriches
 * Spawn in s.
 * Termites spawn in Baobab trees.
 * Meerkats
 * Spawn in s.
 * Moobloom, Glow Squid, and Iceologer
 * In Minecraft Live 2020, there will be a mob vote, similar to the MINECON Earth 2017 biome vote. Since this event is taking place in October 3rd, 2020, the new mob will added to this update, just like the Phantom with Update Aquatic. If it matches with 2017's vote, 1 mob will be chosen out of the three on Twitter and the others will most likely never make it into Minecraft.
 * Will most likely have similar characteristics of their main (like in the game in which they are located in).
 * Moobloom
 * A variant of the Mooshroom/Cow.
 * Spawn in s.
 * Most likely passive.
 * Are friends with bees.
 * Glow Squid
 * A variant of the Squid.
 * Spawn in s.
 * Most likely passive.
 * Will illuminate, being the first entity to do so.
 * Iceologer
 * Most likely an illager.
 * Spawn in.
 * Hostile
 * Hurl ice clouds at the player.

Gameplay

 * Combat?
 * Revamped.
 * As these tests are currently at the end of Phase 1 and there will be Phase 2 only, it may be added in 1.17/1.18.

Biomes

 * s?
 * This biome is from MINECON Earth 2018 and they were stated to be added later.
 * Will have palm trees, meerkats, and oasis.
 * Revamped.
 * Inhabited by Goats.
 * Contains snowier snow and snowy stone.
 * May contain new stone variants.
 * May contain the Iceologer.
 * s?
 * This biome is from MINECON Earth 2018 and they were stated to be added later.
 * Will have baobabs, a new type of tree, termites, and ostriches.
 * Will have baobabs, a new type of tree, termites, and ostriches.

World Generation

 * s
 * Contain Oasis and Palm Trees.
 * Looks more realistic.
 * Have sharper and more jagged peaks.
 * Improved terrain generation.
 * s
 * Contain Baobab Trees
 * Contain Baobab Trees

Blocks and Items

 * Snow
 * If on top of stone, it becomes snowy stone.
 * Stone
 * If snow falls on top of stone, it becomes snowy stone.

Mobs
Note:The changes below may be added in a subsequent update such as 1.18.
 * Villagers
 * Unlocking a trade no longer freezes/crashes the server.

Announcement
1.17 will be announced at Minecraft Live 2020, right at the start, unlike the annoucement of the Update Aquatic, Village & Pillage, and Nether Update announcements. Interestingly, certain devices in are going to be discontinued in October 2020 but this may or may not have anything to to with 1.17.

Fixes
Note:This fix version is 1.17+ meaning they may be fixed in 1.17, 1.17.x, 1.18, 1.18.x, or even later though highly unlikely.