I am making this for the bot in my guild discord mainly, but figured it could be used as a handy resource for those needing to catch up on what they have missed over time.
The following is a list of the different updates that we have received and a table of contents for each.
February 2020 Update Guide
I: Musketeer Awakening
II: Alchemist Awakening
III: Changes To Musk/Alch
IV: Maid Balance Patch
V: Earth Of Confusion
VI: Ring Prefix System
VII: New DXU Items
VIII: Unique Disassembly Rework
IX: Relic Gear Rework
X: New Nephon Creatures
XI: Secret Dungeon Changes
XII: New Secret Dungeons
XIII: New Elite Pets
XIV: Quality Of Life Improvements
XV: Misc
May 2020 Update Guide
I: Status Condition Rework
II: PvE & PvP Skill Changes (Split into PvE and PvP sections)
III: Batch Disassembly of Unique Items/Magic Ink/Nephon Creatures
IV: Siege War Rework
V: New PvP Weapons (Crow/Cheyenne)
VI: Smelting
VII: New Sub Quest
VIII: EoC Ranking System
IX: New Nephon Creatures
X: New Prefixes + Changes to 3 Prefixes
XI: Misc
August 2020 Update Guide
I: Unique Drop GFX
II: New Lv850+ Quest
III: New Maps
IV: New Raid Boss (w/additional special GFX)
V: Guide System
VI: New Nephon Pets
VII: 6 New Quests for Lv700+
VIII: Secret Dungeon Changes
IX: Tamer Balance Patch
X: Werewolf Balance Patch
XI: Demon Balance Patch
XII: Lancer Balance Patch
XIII: New UMU Weapons/Armor
XIV: Transcendence Skill Changes
XV: Misc
November 2020 Update Guide
I: Squire Balance Patch
II: Princess Balance Patch
III: New Auxiliary Weapons
IV: New Surag Difficulty
V: New Quest
VI: Mission Book Season 3
VII: Nephon Quality of Life Updates
VIII: Notes
March 2021 Update Guide
I: Opticalist Balance Patch
II: Thief Balance Patch
III:PvP/PvE Balance Patch
IV: Dimension Hub (Lv 900~1250)
V: Breaking the Limit improvements
VI: Mirror Fields added to high level areas
VII: Guild War/Siege War only consumables added
VIII:Additional Rapid Growth Equipment
IX: Quality of Life changes/Additional Changes
X: Notes
I: Yatikanu Woods
II: New Episode & Sub Quests (1250+)
III: New Auxiliary Weapons
IV: New Nephon Creatures (and new nephon skill)
July 2021 Update Guide
I: Magic Archer Balance Patch
II: Demon Sorceress Balance Patch
III: Beastman Balance Patch
IV: Yatikanu Woods Rework
V: Dimension Hub Rework
VI: New Nephon Creature
VII: Equipment Upgrade UI Rework
VIII: Costume UI Rework
IX: Other Quality of Life Updates
September 2021 Update Guide
I: Yatikanu Woods Rework
II: Costume Upgrade System
III: Costume UI Improvements
IV: 2 New Maps
V: New Episode Quest
VI: New Sub Quests
VII: Notes
November 2021 Update Guide
I: Daily 900 "Daily" 800 Boss Rework
II: Equipment Enhancement UI Improvement
III: Alchemist Mini-Rework
IV: New Potions
V: Paid Item Probabilities
VI: SD Party System Rework
VII: Misc.
January 2022 Update Guide
I: New PvP Maps
II: New Quests
III: Cemetery/Hector Quest PT2
IV: New Nephon Creatures
V: Notes
March 2022 Update Guide
I: Balance Patch for Various Classes
II: Nephon Pet Changes
III: MQ1 and MQ2 Changes (Quality of Life Updates)
IV: Darlene/Delan/AR1&AR2 Changes
V: Rebirth/Raid/NPC Changes
VI: Notes
May 2022 Update Guide
I: New 800+ Hunting Fields
II: New Episode Quest
III: New Sub Quests (4)
IV: Notes
I: New Class- Captain (insert Oh Captain My Captain reference here)
II: Lv1000 UMU & 1100 DXU Equipment
III: Maximum Level Increase
IV: New Hunting Fields Added (1400+)
V: Existing Map Improvement
VI: Changed Modeling of 2 NPCs
VII: Elite Suppression
VIII: Set Prefixes (New Enchantment)
IX: Improved Ether Machina
X: Improved Nephon Creature Function & Adventure
XI: Black Market Dealer (Yatikanu)
September 2022 Update Guide
I: New Hunting Field
II: New Episode Quest (Colliding Two Stars, Lvl 1050+)
III: New Sub Quests (Lvl 1100+)
IV: Notes
November 2022 Update Guide
I: Captain Awakening
II: Various Balance Patches
III: Improved Skill Usage Convenience (Bottom Left Skills)
IV: Transcendence Skill Balance Patch (+Additions)
V: Quality of Life changes
VI: NPC Model changes
VII: Prefix Balance Patch (+Additions)
VIII: Land of Chaos (aka: Earth of Confusion) changes
IX: Treasure Map System changes
X: Inventory and Minimap Expansion
I: New Sub Quests
II: New Nephons & New Nephon Features
III: Notes
March 2023 Update Guide
I: Monk PvP Balance Patch
II: 1250 UMU Weapons
III: 1250 UMU Armor
IV: Maximum Damage Limit Increase
V: Change of NPC Models
VI: Grinding Slot Option Converting System
VII: Various Content Reward/Loot Changes
VIII: Mirror Field Changes/Additions
IX: Lvl 1500+ Content Participation Difficulty Decreased
X: Notes
May 2023 Update Guide
I: Abyss difficulty added to ES/Elite Supes
II: Added fancy health bar to ES/Elite Supes
III: New Episode Quest
IV: New Sub Quest
July 2023 Update Guide
I: Tamer Rework
II: Summoner Rework
III: Enhanced Association Equipment
IV: Dimension Hub Rework
V: Premium Field Improvement and Additional Another-World Monster
VI: Returner Rework (RT+)
VII: Added Knockout Popup
VIII: Notes
September 2023 Update Guide
I: Uposmeyer Field
II: Uposmeyer Auxiliary Items
III: Notes
April 2024 Update Guide
I: Champion Balance Patch
II: Mythic Nephons
III: Nephon Transcendence
IV: Purple Magic Stones/Crests (Costume System)
V: New Suppression Boss UI + WEEKLY Suppression Bosses
VI: Dimension Hub Changes (added: Yatikanu range)
VII: Misc
VIII: Notes