Via [url=https://list.valvesoftware.com/cgi-bin/mailman/listinfo/hlds]HLDS[/url]:

[quote=Valve]- Improved Steam Voice support for servers that have enabled it
- Removed sv_use_steam_voice convar. Steam voice is now selected via "sv_voicecodec steam"
- Fixed demos not properly recording Steam Voice status, resulting in potential corrupt voice in demos with differing default settings
- Will now use the native Steam Voice sampling rate, instead of clamping to 11kHz
- Improved compatibility with Steam client beta
- Fixed OS X voice communication sounding high-pitched when using the default CELT voice codec
- Fixed an animation bug that would cause the client and server hitboxes to become out of sync
- Fixed the Scout not playing the correct animation when using the Shortstop's Alt-Fire to shove someone
- Fixed some missing VO sounds for the Scout when he picks up a baseball
- Fixed Spectators seeing the fake death notices for the Spy when he feigns death
- Fixed the Widowmaker not doing increased damage when the Sentry's target is a building, boss, or tank
- Fixed not earning Crikey meter progress with The Cleaner's Carbine when damaging a building, boss, or tank
- Fixed the Scout not getting assists for shoving players while using the Shortstop
- Fixed not being able to use non-tradable Giftapults
- Fixed powerups sometimes being removed from the game in Mannpower mode
- Fixed a case where the scoreboard would not update properly when players volunteer to switch teams in Casual mode
- Fixed a case where Casual servers would spontaneously terminate with "Server shutting down" upon losing connection with the matchmaking service
- Updated the logic used to pick the maps players can vote on in the end-of-match map vote on Casual servers to help maintain healthier game mode representation across regions
- Casual servers were often rotating to unrelated game modes during votes, resulting in partially filled servers in certain regions
- Updated the player_bodygroups that are hidden when equipping The Dark Falkirk Helm and The Sole Saviors
- Updated the model/materials for The Snowmann to fix some LOD issues
- Updated the localization files
- Added Gift Wrap back to the Mann Co. Store at a reduced price
- Added TF2Maps 72hr TF2Jam Winter Participant 2017 community medal
- Added Rally Call Charity Tournament community medals
- Added ozfortress Season 18 tournament medals
- Added new survey questions to the end-of-match survey for Casual and Competitive modes and fixed a bug where multiple surveys could be displayed at the same time[/quote]

Rumor has it:

- The new survey questions are intended for those that don't frequently play casual or competitive, and one to rank quality of maps: http://i.imgur.com/0tnfHQh.png

- sigsegv__ (a responsible bug hunter) [url=https://www.reddit.com/r/tf2/comments/5u2s53/tf2_update_for_21417/ddqwdus/]tells us a tale about the origins of the animation-related hitboxes bug[/url] originally discovered by Nicknine from TF2 Classic and reveals that this bug's been happening ever since The Orange Box was released in 2007

- A few HUD file updates and a local sync of Steam Datagram system configuration changes from the past month: [url]https://github.com/SteamDatabase/GameTracking-TF2/commit/537a93b69227c91d3a58d852fe6be48032faed6f[/url]

- Here's [url=http://git.optf2.com/schema-tracking/diff/?h=teamfortress2&id2=55b0a13107ba355fd01dd1e8558ce140692adf00]the updated item schema[/url], featuring the ozfortress medals, but no UGC medals

- Size is ~40 MB