From Minecraft Parkour Wiki
This article lists all parkour-related changes in newer versions of Minecraft (1.9+).
Changes are grouped into 3 categories:
Movement : Changes or additions to movement mechanics.Blocks : New blocks, or changes in current blocks' properties.Other : Changes that should be mentioned, but don't really impact standard parkour.
1.9
Category
Changes
Movement
Jump height increased (from 1.249 to 1.252). Momentum threshold has been lowered (from 0.005 to 0.003).
This is the reason why jump height is different, as well as taps . Sneaking now lowers the player's bounding box (from 1.8m to 1.65m).
Blocks
End rods added (0.25×1×0.25 bounding box, can be placed in all directions).
Chorus plants added:
Default: centered 0.625×0.625×0.625 bounding box (generally the same height as an end portal frame).
Connects to adjacent chorus plants and flowers. Also connects to any ground below it.
Chorus flowers have a simple 1×1×1 bounding box.
Shulkers added (technically entities) - 1×1×1 bounding box, but can rise by 0.20609b.
Grasspath added: 1×0.9375×1 bounding box
Ladders are now 1 pixel wider (from 0.125b to 0.1875b)
The bounding box of pane blocks have changed:
The neutral variant is no longer a cross, now it's just a 2 by 2 pixels pole.
The internal segments are 1 pixel longer.
Lilypads are now 0.09375b tall (1.5 pixels) and 0.875b wide (reduced by 1 pixel on all sides)
Boats (technically entities) are now 0.5625b tall (instead of 0.6b).
Bugfix: Piston heads now match their model:
The arms now have the correct width (0.25b).
The arm's length is extended by 0.25b, making piston heads the only block that can protrude horizontally onto adjacent blocks.
The west-facing extension is no longer bugged.
Bugfix: Chests and Anvils now have a fixed bounding box.
Other
Elytras added.
Levitation effect added.
Entities now push the player when colliding.
Falling on a hay bale absorbs most of the fall damage.
1.10
Category
Changes
Movement
Added "Auto-jump" option in the Controls tab. When toggled on, it automatically makes the player jump.
Auto-jump does not activate while sneaking.
Auto-jump activates
Notable uses include: 100% strat for hh 1+1 jumps, easy way for grinding on stairs aka "slab-boosting".
Blocks
Added Magma block, which damages the player when they are standing on it, unless they are sneaking.
1.10.1: Farmland is now 0.9375b tall (15px), instead of 1b.
Other
New Debug shortcut: F3+G shows chunk borders.
1.11
Category
Changes
Movement
Sneaking now prevents falling more than 0.6b (previously 1b)
Blocks
Shulker Box added - 1×1×1 bounding box, can extend by 0.5b when opened with right click.
The extension increases and decreases by increments of 0.05b every tick.
The shulker box can only be opened if it doesn't end up intersecting with another bounding box.
Interestingly, the opening starts with a surplus of 0.01b, which means the player is actually pushed 0.51b.
Other
1.12
Category
Changes
Movement
Blocks
Beds now have bouncing properties:
Only converts 66% of the player's downward speed, unlike slime blocks which are 100%.
Fall damage is reduced, but not completely negated unlike slime blocks.
Walls, Fences, and Panes/Bars now connect to the backside of stair blocks.
Other
1.13
Category
Changes
Movement
Water movement revamped: sprinting in water now puts the player in a swimming state, which has many useful properties.
Blocks
Some blocks can now be waterlogged , allowing for more jump possibilities.
Wall blocks now have a more accurate bounding box.
Other
1.14
Category
Changes
Movement
X/Z collisions changed, the first direction processed now depends on the player's velocity.
Ladders and vines can now be climbed by pressing jump.Sneaking lowers the player's bounding box even more: (from 1.65m to 1.5m)
You can now fit under 1.5b ceilings
Forcing the player under ceilings lower than 1.5b activates the swimming state.
This can be done by using a piston or trapdoor.
Bugfix?: Blips have been patched: the player can no longer abuse stepping mechanics to gain jump height.
You can still clip onto the side of blocks when falling down.
A new glitch was introduced: "blip-down ", which happens when activating stepping on the edge of a block.
Bug: you can conserve X speed when moving into a corner.
Blocks
Movement on soulsand has been slightly tweaked.
...
Other
1.15
Category
Changes
Movement
Slipperiness changed: only blocks below 0.5b of height are affected by slippery blocks.
Soulsand is no longer affected by ice and slime slipperiness.
Blocks
Other
1.16
Category
Changes
Movement
Blocks
Other