Via [url=https://steamcommunity.com/games/CSGO/announcements/detail/526494450238621926]the Steam Community[/url]:

[quote=Valve][b][u]MISC[/u][/b]
- Mitigated a performance issue that primarily affected Windows 10 users with recent Intel CPUs.
- Fixed a case where the Delete Item inventory option wasn't working.
- Fixed a case of visual corruption using iron sights on AMD GPUs.
- Expanding list of console variables addons are allowed to change.

[b][u]MAPS[/u][/b]
[b]Overpass[/b]
- Fixed the Party balloons.[/quote]

Rumor has it:

- Size is close to 525 MB (with Workshop Tools installed)