Valve has released a new update for CS:GO which reintroduces the Negev and the R8 Revolver in Competitive Matchmaking.
The official patch notes are listed below:

– Added Holiday Cheer.

– For a limited time, the Negev and R8 Revolver are available in Competitive Matchmaking.
– R8 Revolver: Price reduced to 700
– Negev: Price reduced to 2000 as a starting point, to promote experimentation with the weapon

– Volume now decays smoothly over distance, instead of by discrete steps.
– Adjusted HRTF audio mix to more closely match sound quality without HRTF.
– Added snd_hrtf_distance_behind (default 100), which allows HRTF to more closely match the perceived direction of a sound source as seen by the actual player behind a monitor.
– Fixed a bug where music volume would be set to the maximum level while accepting a lobby invitation.

– Added support for official game servers in Guangzhou and Shanghai for the Perfect World CS:GO Beta.

– Added Team ID option “Always On w/Equipment” to Game Settings
– Spectators can now use overhead equipment display.
– Fixed overhead equipment display not updating in some cases.
– Fixed orientation of stickers on dropped weapons.
– Adding Game State Integration output for use by tournament organizers. New output for player equipment value (with log_level 3), showing the observer slot for each player and adding a new ‘PhaseCountdowns’ feed for timing the end of warmup/freezetime/round ends.