(1.21.6+) Next to Aspect Effect names now is a hover symbol [+] which will tell exact numbers and triggers for that Aspect Effect
(1.21.6+) Much like above feature, at the end of Aspect Effects will be a hover entry that will show all combined triggers and statistics of that Aspect
(1.21.6+) Added missing Essence Types in Essence List Dialog screen
Aspects with unique starter items now validate themselves if they are missing that item, or if it should exist on them to begin with
Custom Items now show their Use Time first, instead of Cooldown
Custom Items now show their exact timers for Use Time and Cooldown instead of ambiguous terms
Essence Cage can now store Essences in both hands
(1.21.6+) Players without Aspects now are heavily debuffed (can be disabled via scoreboard configs)
Aspect Changes
Elytrian
Reduced extra Attack Knockback when Elytra Flying to +0.5 (was +1.0)
No longer has reduced Scale, now its the same as a Human
Elytrian's Wings are now damaged twice as much when using Firework Rockets
Feline
Fixed descriptions not mentioning it has Night Vision
No longer gets passive Speed boost and Movement Efficiency
Predator can now trigger if you have Speed Potion Effect
Predator: Pursuing now grants +10% Attack Speed and +1.0 Movement Efficiency
Predator: Recovering now grants -20% Attack Speed and -100% Movement Efficiency
Focus now can be used mid-air, but is slightly weaker when used on the ground
Infernal
Effects that require to be On Fire now count if the required entity is visually On Fire too
No longer removes Hunger
Passive Status Effect removal now requires to be On Fire
Cooking food is now 8 seconds (was 15) and doesn't require 2 stages, now it's done at once
Cooking food requires to be On Fire
Focus now ignites self for 16 seconds (was 12) (cooldown unchanged)
Merling
Fixed descriptions not mentioning it has Night Vision
Outside of Water mining speed penalty is now -25% (was -20%)
Moisture now starts at 20 seconds (was 15) and restores after 6 seconds at most (was 4)
Moisture respiration scaling now is 10 seconds per level (was 15)
Moisture now pauses instead of being restored when Water Breathing is active
Technical Changes
The entire datapack was restructure and re-done, if you were working with v1.0.2 and before, good luck.
A guide will be available soon™
Extra Notes
Due to the technical changes, bugs that were not there before are more likely to show up, but we tried to make it as seamless as possible to transition to the new format, however if something unexpected comes up reports are very much welcome like usual.