Via CS:GO Blog:

PERFECT WORLD

• Added UI to see current Perfect World account balance and add funds from the main menu.
• Added ability to purchase keys outside of case opening.

OPERATION HYDRA

• Operation Hydra passes are now 50% off.
• Fixed a rare case where Operation Hydra rewards were earned at reduced rate for accounts who maxed out their regular weekly XP.
• Fixed an issue where the Operation Hydra UI erroneously claimed that more stars would become available next week.
• Fixed an issue that caused some UI elements to show a gold operation coin for users with diamond coins.
• Removed weekly “Operation XP Exhausted” end-of-match warning for players with the maximum amount of event stars.

MISC

• Fixed some cases where footstep sounds would not be heard. Thanks to /u/Jambozx for his video demonstration this issue.
• Updated Mac-10 | Oceanic to have more randomness in the texture pattern.
• Fixed several security exploits (thanks Sikari!)