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

[quote=Valve]- Updated cp_gullywash_final1 to fix func_rotating entities not working in the skybox
- Updated some of the cosmetic items from the Winter 2018 Cosmetics Collection to fix missing styles[/quote]

Rumor has it:

- Strings and an item schema update for missing styles: https://github.com/SteamDatabase/GameTracking-TF2/commit/8b1da2b1dec12ccc7a3f3dff75e75cb5c37fb52c

- Size is ~30 MB

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[b][url=https://support.steampowered.com/kb_article.php?ref=1558-AFCM-4577]Valve will end its support of Steam on Windows XP and Windows Vista in two weeks, on 1/1/19.[/url] Additionally, [url=https://support.steampowered.com/kb_article.php?ref=5953-QTIO-1764]Valve is also ending its support of Steam on Mac OS X Lion, Mountain Lion, Mavericks, and Yosemite on 1/1/19 as well.[/url][/b] Any future TF2 updates that moves the minimum Steam client version beyond the last one available for XP/Vista will render it unplayable unless you upgrade Windows. Any future TF2 updates that moves the minimum Steam client version beyond the last one available for Lion through Yosemite will also render it unplayable unless you grab Mac OS X El Capitan or newer from the Mac App Store.