Via [url=http://blog.counter-strike.net/index.php/2017/08/19236/]the CS:GO blog[/url]:

[quote=Valve]The following changes are in the “1.35.9.8-rc1” CS:GO Beta depot.
[GAMEPLAY]
– Shipping more changes to pistols with the goal of emphasizing skillful use of the weapons.
– Five-SeveN: The Five-SeveN has been adjusted to reward tactical positioning and defensive play.
— Slightly improved accuracy when firing several shots rapidly.
— Substantially reduced accuracy while moving.
[PERFECT WORLD]
* Prime status is now immediately granted to Perfect World accounts with identity verification.
* Enabled support for custom avatars in game.
* Enabled access to the developers console.
[MISC]
* Overhauled internal weapon data representation. All weapons are expected to behave identically to 1.35.9.7 aside from the Five-SeveN and bugfixes listed below.
* Fixed an issue that caused players to not drop their 2nd flashbang if they are killed after throwing 1 flashbang during the round.
* Fixed an issue where sniper bots didn’t like the Scar20.
* Fixed an issue where buying non-weapon items would restock ammo for all your weapons.
* Fixed some corner cases where buying items via console could ignore the user’s loadout selection.
* Fixed an issue where attempting to drop undroppable items (like grenades) would count the items value towards the player’s “donations” for the round.
* Fixed a rare issue that could cause players to show incorrect holstered weapons.
* Fixed an issue where decoy grenades could make sounds from the wrong weapon.
* Fixed “buy” console command to list all options instead of being a hardcoded help string.
* Map editing: env_gunfire entities can now fire all weapon types (e.g. weapon_m4a1_silencer or weapon_revolver)
* Fixed a memory leak related to spectating.
* Adding ability to initiate trades from friend’s context menu.
* Improved map load times in some circumstances.[/quote]

Rumor has it:

- /u/SlothSquadron [url=https://www.reddit.com/r/GlobalOffensive/comments/6tyu0t/counterstrike_global_offensive_prerelease_update/dlom94m/]is working on a breakdown of the Five-SeveN changes[/url]

- Wish to opt in? Right-click on CS:GO in your Steam library, go to Properties, go to the Betas tab, then select "1.35.9.8-rc1"
- [b]If you don't see this branch offered, restart Steam[/b]
- To opt in for servers: run "app_update 740 -beta 1.35.9.8-rc1" in SteamCMD
- Valve servers will almost definitely be unavailable as has been the case with the last few prerelease tests

- SteamDB GameTracking services will be completely unavailable as it only keeps eyes on the public branch - be aware

- Size is close to 20 MB