Via [url=http://blog.counter-strike.net/index.php/2016/06/14740/]the CS:GO blog[/url]:

[quote=Valve][MISC]
– Replaced the penalty for the suicide or disconnection of a player. Instead of the elimination of round-end income, a living enemy player now receives compensation equal to the missed kill reward opportunity.
– On Valve official servers, the current map will be excluded from the vote options at the end of a match.
– Modified behavior of mp_endmatch_votenextmap_keepcurrent (default 1). When set to 0, the current map will be excluded from the end of match map vote panel.
– Full player hitboxes are now used by “cl_weapon_debug_show_accuracy 2” so that the circle appears closer to the target in 3D space.
– Fixed coin journal not being accessible from inventory UI.
[OSX/Linux]
– Made it so “Fullscreen” sets an exclusive fullscreen mode and “Windowed Fullscreen” sets a non-exclusive fullscreen mode. Exclusive fullscreen mode allows for potentially higher performance while making switching back to the desktop slower.
[SPECTATING]
– Added the concommand spec_player_by_accountid that switches observer target to the player with SteamID64 passed as argument.
– Added the convar spec_lock_to_accountid which, when set, will lock the observer target to the specified SteamID64 player. The lock can be set regardless of whether or not the player is currently connected.
[MAPS]
Cbble:
-Added stairs up to B site platform, giving CTs additional options for defending the site
-Updated trees with more accurate collision model
-Fixed rendering error on wall hole model used near bombsite A
-Fixed various bugs (Thanks csgobugtracker.com contributors!)
-Improved visibility from underpass to A site
Mirage:
-Fixed pixelwalk in CT spawn
-Fixed some small seethrough gaps in bombsite A
-Fixed small seethrough gap from Short to Mid
-Fixed grenadecollision on van in bombsite B
-Van now plays proper surface sounds when walking on it
-Stairs in palace and B apartments will now play correct surface sounds
-Fixed potential rendering error on wall hole model used in CT sniper position
-Fixed various bugs (Thanks csgobugtracker.com contributors!)
Cache:
-Minor bug fixes
Nuke:
-Added ladder to bombsite B target
-Top of bombsite B target now opaque
-Added short crate stack to CT outside
– Misc clip fixes
[quote=Added at the request of /u/j_cliffe, these two are missing in the source]- Improved vcollide on plastic bins
- Fixed spot at CT spawn where weapons could be lost[/quote]
Collision model update:
-Added more accurate collision model for bombsite models used in Mirage, Inferno, Cache.
-Added more accurate collision model for barrels used in Overpass B site.[/quote]

Rumor has it:

- PM confirming the two missing notes are in fact legitimate: [url]http://i.imgur.com/wCrVBTT.png[/url]

- Worried about this update screwing things up in the ESL One Cologne 2016 qualifiers? A previous version branch was made available yesterday named "1.35.3.5" for anyone that wants to revert for whatever reason
- In fact, [url=https://twitter.com/crtmn/status/741059122800558081]there's already confirmation that the old versions of maps will be used[/url]

- Nuke got a new image for use in places such as the load screen, UI elements such as map picking, and in areas such as the Steam Workshop for future compatibility versions: [url]https://github.com/SteamDatabase/GameTracking/commit/9525d61a3b02d9c3458b69b1e383a17e07bb1ddc[/url]

- Lots of low-level things that probably won't make much sense to anyone: [url]https://github.com/SteamDatabase/GameTracking/commit/aaf70549d59dc8dcdb4a7473239dd75a394f4efd[/url]

- Size is close to 100 MB