Via [url=https://list.valvesoftware.com/]HLDS[/url]:

[quote=Valve]- Fixed XP-earned text being truncated for some clients
- Fixed some missing particles when running in DirectX8
- Fixed the Athenian Attire not being paintable
- Added server ConVar "sv_downloadlist_include_navfile" to control downloading .nav files to clients (disabled by default)
- Added ESEA 6s Invite Season 29 and Season 30 tournament medals
- Added Brazil Fortress 6v6 Season 1 and Season 2 tournament medals
- Updated the LODs for the TFNew tournament medals
- Updated the Roaring Rockets unusual taunt particle effect
- Updated pl_rumble_event
- Fixed bumper car head start not being awarded correctly to the winning team of the normal world
- Fixed Merasmus announcing winner of the bumper car race twice
- Fixed players sometimes getting stuck on closing doors
- Added spawn locations for the collectable soul gargoyle in the normal world
- Increased sound distance for the flying sawblades so they can be heard from farther away
- Improved clipping in the underworld race area
- Updated pl_millstone_event
- Fixed an issue where players were able to trap Headless Horseman above the death pit
- Updated pd_cursed_cove_event
- Fixed missing materials
- Updated koth_slasher
- Fixed an inconsistent set of func_nobuilds at mid
- Fixed a spot where Engineers could hide buildings in trees
- Fixed players being able to build on top of the spawn rooms
- Updated koth_bagel_event
- Entering the underworld now puts players back to full health
- Players will no longer fall off the platform if they enter the underworld while moving backwards or sideways
- Added a couple pumpkin spawn locations in the underworld
- Minor visual update to underworld exit[/quote]

Rumor has it:

- If you want to have a look at item schema changes, [url=https://github.com/SteamDatabase/GameTracking-TF2/commit/4c864b9de26cf07638e39a39877adadb53be8ce0]GameTracking's the place to do it[/url]

- Size is ~140 MB