Hey, we're pushing an update for Garry's Mod right now. You'll still be able to play on any servers that have not yet been updated.

There's some more in-depth information on the update here.

It might take up to 15 minutes for the update to pop up on Steam.

Game Changes
NEW - Preset support for Utilities menus
NEW - 'Quick Preset' button - allows for easier access to the preset system
NEW - Addons menu can now manage multiple addons at once (e.g. bulk unsubscribing)
NEW - Demos, saves, and duplications menus now list items that the user is subscribed to
NEW - Addons menu now has a search bar to quickly search through subscriptions
NEW - The '-notty' startup parameter on Linux servers will send console output directly to stdout
UPDATED - Weapons no longer turn upside-down when zooming in too far
UPDATED - Improved support for CS:GO/Portal 2/TF2 maps
UPDATED - Game returns to DirectX 9 mode if '-dxlevel' is not specified in the command-line
UPDATED - Improved relationships between Half-Life and Half-Life 2 NPCs
UPDATED - Improved behaviour of collisions between players and 'no collided' entities created by tools
UPDATED - Added more information to crash dumps (.mdmp files)
UPDATED - r_eyes_* console variables are no longer saved
UPDATED - The emitter tool's explosion effect no longer creates sounds
UPDATED - Bots can longer be created before the InitPostEntity hook has fired
UPDATED - Improved how serverside ragdolls are handled on the client - hull traces can hit them now
UPDATED - Updated the Half-Life Model Viewer to have newest features from Team Fortress 2 veresion
FIXED - Odessa no longer has female voices
FIXED - Fixed errors caused by the spawn menu's search feature not having access to certain directories
FIXED - Fixed many crashes related to NPCs trying to use non-existent entities
FIXED - Checkboxes and radio buttons in HTML panels are now displayed properly on Linux/macOS
FIXED - Half-Life Ichthyosaur can now cause damage
FIXED - Half-Life Tentacle NPC no longer continues playing sounds after being removed
FIXED - Fixed massive FPS drops when missing sounds are playing on servers
FIXED - Fixed crash that occurs when console variables created by Lua are removed too early on level change
FIXED - Fixed late loading of memory allocator on Linux causing the game to crash for some people
FIXED - Impulse 200 command no longer crashes when the player has no active weapon
FIXED - Fixed prediction errors when firing weapon_357
FIXED - weapon_357 now has the 'revolver' holdtype

Lua API Changes
NEW - Entity:PhysicsInitStatic( ... )
NEW - Entity:RemoveCallback( ... )
NEW - Entity:GetCallbacks( ... )
NEW - CLuaEmitter:IsValid( ... )
UPDATED - Entity:PhysicsInit* methods now return either true or false based on success
UPDATED - Entity:Remove() can no longer remove the world
UPDATED - Weapon:IsScripted() will now return false instead of no value when ran on non-scripted weapons
UPDATED - Player:Give( ... ) no longer fills a player's gun with ammo when asked to not give ammo to players
UPDATED - Entity:GetBoneCount() and Entity:GetBoneParent( ... ) will now return -1 on failure
UPDATED - Entity:TranslateBoneToPhysBone( ... ) will now return -1 on failure
UPDATED - Entity:SetSaveValue( ... ) now returns false on failure
UPDATED - Entity:DispatchTraceAttack( ... ) will now trigger an error when passed invalid parameters
UPDATED - Entity:HasBoneManipulations() and Entity:HasFlexManipulatior() return false on failure
UPDATED - Entity:GetBrushPlaneCount() will now return false on failure
UPDATED - Entity:GetFlexScale( ... ) now always returns 1 on failure, rather than just sometimes
FIXED - Entity:GetBrushPlaneCount() and Entity:GetBrushPlane( ... ) now work on brush entities
FIXED - PathFollower:Compute() no longer leaks Lua references

Hammer Changes
UPDATED - Improved performance of 2D/3D views
UPDATED - 2D views are now rendered during scroll operations, rather than after
UPDATED - Increased max render distance from 10,000 to 32,000
UPDATED - Vertices no longer need to be in the exact same location to be merged
FIXED - Blended textures are now rendered correctly - it should be identical to in-game
FIXED - Model browser no longer freezes after being opened multiple times
FIXED - Overlays no longer flicker when rendered in 3D shaded mode
FIXED - Scrollbars on 2D views are now correctly sized when zoomed in

GitHub Pull Requests
UPDATED - Removed CAP_INNATE_RANGE_ATTACK1 from weapon_base
UPDATED - Removed unused function parameters
FIXED - Result of COLLISION_GROUP_DEBRIS trace in properties.Gethovered is no longer ignored
FIXED - Fixed use of non-existent enum in DModelPanel
FIXED - Fixed 'Cannot set property' JavaScript error in main-menu
NEW - Trouble in Terrorist Town: Enabled scoreboard to be sorted by different criteria
UPDATED - Trouble in Terrorist Town: Corpses get skin/bodygroups of dead players
FIXED - Trouble in Terrorist Town: Fixed incorrect fall damage
FIXED - Trouble in Terrorist Town: Fixed 2 DoS exploits