Via [url=https://blog.counter-strike.net/index.php/2019/01/22737/]the CS:GO blog[/url]:

[quote=Valve][MAPS]
– Added a new version of Vertigo to Wingman official matchmaking.
– Added Zoo and Abbey to Casual and Deathmatch official matchmaking.
– Removed Austria and Subzero from official matchmaking.

Biome:
-Improved performance.
-Removed connector between A short and A long.
-Removed mid lower entry.
-Added ladder to mid upper entry.
-Moved T spawn towards A to give CTs better mid timings.
-Fixed several bomb stuck spots and clipping issues.

[MISC]
– Accounts are now automatically upgraded to Prime by reaching Lieutenant Rank 21.
– Fixed a regression for some Perfect World accounts with completed Identity Verification and restored their Prime Account Status.
– Fixed scoreboard team names truncation in some languages.
– Fixed random map behavior in offline with bots game modes.

[SOUND]
– Adjusted velocity value for when jump ‘step’ sound plays for more consistent behavior.
– Fixed a bug where player fall damage sound wasn’t playing most of the time.
– Fixed a bug where “the bomb has been defused” and “counter-terrorists win” VO lines could overlap each other.[/quote]

Rumor has it:

- Size is ~250 MB

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[b][url=https://support.steampowered.com/kb_article.php?ref=1558-AFCM-4577]Valve's support of Steam on Windows XP and Windows Vista has ended on 1/1/19.[/url] Additionally, [url=https://support.steampowered.com/kb_article.php?ref=5953-QTIO-1764]Valve's support of Steam on Mac OS X Lion, Mountain Lion, Mavericks, and Yosemite also ended on 1/1/19 as well.[/url][/b] Any future CS:GO 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 CS:GO 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.