1.10 Update:

General:

-Knives can now spawn in the campaign (this was supposed to be in the previous update)
-Some primary weapons and Magnum pistols throughout the campaign may now spawn using alternate skins

Level 1 (Garage):

-The map is now longer and features a new "fictional" start
* The original starting area has been altered as a result
* Added new weapon/item spawns into the new/altered areas
-Some minor balancing changes related to the new level structure
-Fixed an issue where hordes could appear from a dead end during the garage door panic event
-Added some props to various empty shelves across the level

1.9 update re-released since I forgot to increase the in-game version count (would have caused matchmaking issues)

1.9 Update:

General:

-Added support for Last Stand content
* CS weapons can now spawn throughout the campaign
* Shovels can now spawn in certain locations

Level 1 (Garage):

-Improved the weapon spawns in the back of the police car (shotguns should no longer glitch into the car)

1.8 Update:

-Change mission name from "CSOffice" to "CSOfficeForL4D2"
-This fixes a conflict with another similar add-on

Level 1 (Garage):

-Fixed a potential exploit related to throwing bile bombs on top of awnings
-Fixed a rare case where common infected could spawn on top of the wall trim near the end of the map

Level 2 (Interior):

-Exploit fixes similar to the first level
-Added 4 new item spawns
-Added static elevator button props next to the elevator doors
-Fixed a potential pain pills spawn hovering slightly above the ground

1.7 Update:

General:

-Added a new loading screen (similar to De_Port)
-The maps are now numbered in the level selection list
-Fixed console error message caused by a missing bracket in the mission file
- All levels now have a new, more detailed 3D skybox
* Updated the 1st and 3rd level images to reflect this
-Fixed a potential crash related to stringtable dictionaries
* NOTE: This issue can still persist/re-emerge if you have lots of add-ons (or several very large ones)!
-Tweaked the fog in all levels

Level 1 (Garage):

-Fixed a misplaced spawner that could make an item clip into a shelf
-Fixed several console error messages caused by entities left behind from the porting phase
-Fixed a potential exploit related to pipe bombs/boomer biles that could be used to stop common infected in their tracks
-Fixed several prop fades left over from the original map

Level 2 (Interior):

-Removed a remark entity that could make Nick and Rochelle speak lines from Swamp Fever
-Added a few new item spawns around the map + made some existing spawns have a wider selection of potential items
-Fixed an issue where the game would consider the Survivors as having left the starting safe
area when they actually hadn't
-Fixed the map having a different looking sky than the other maps
-Fixed a minor visual problem with the inset ceiling lights

Level 3 (Rooftop Finale):

-Finale radio overhaul:
* Added 8 new lines for the radio operator and chopper pilot
* Most lines now display subtitles
* The pilot will now periodically tell you to get into the chopper (these do not display subtitles as not to interfere with Survivors speaking)
-Improved helicopter sound positioning
-Reduced the maximum yaw of the mounted machine gun to 80 degrees (was 90)
-Fixed a minor visual problem with the inset ceiling lights in this level, too
-Fixed the lawn chair props floating slightly above the roof
-Fixed infected not dying if they were lured to certain areas on ground level by a bile bomb or pipe bomb
-Added proper windows to the exterior wall
-Improved infected pathfinding outside of the fenced finale area

1.6 Update:

General:

-Several navigation mesh improvements throughout the campaign
-Updated map preview icons for levels 1 and 3
-Updated cubemaps (reflection maps) for all levels
-Updated Steam Workshop images

Map 1 (Garage):

-Fixed one item spawn potentially clipping the item into the floor
-The game no longer considers survivors as having left the starting area until they go past the roll-up door
-Minor detail additions

Map 2 (Interior):

-Changed the interior floor textures to better match the original map
-Fixed one of the sofa chair props fading out at unintended distance

Map 3 (Rooftop Finale):

-Interior floor texture changes similar to the previous level
-All survivors now have three different randomly picked lines for when the rescue chopper arrives (instead of Coach's single line)
-Triggering the finale now locks the saferoom door into open position (prevents an exploit)
-Minor detail additions

1.5 Update:

General:

-Fixed console spam caused by missing textures left over from porting phase

Map 1 (Garage):

-Added an additional grenade launcher spawn
-Fixed two potential exploits spots where bots could not reach players

Map 3 (Rooftop Finale):

-Fixed a small nav issue within the infected-only area
-Improved the end cinematic:
*Players can no longer see themselves being "teleported" to safety
*Players are no longer left vulnerable for .3 seconds after all survivors have entered the chopper
*Removed the first fade-in as a result of the above points
-Minor visual tweaks and improvements

1.4 Update:

General:

-Added survivor responses to all levels (they will now comment on nearby safehouses and give direction hints, for example)
-Randomized Magnum pistol spawning (33%, 50% and 33% chance in first, second and third level, respectively, but always atleast 1 per level)
-Clients should no longer be able to connect to servers running an outdated version of the add-on

Map 1 (Garage):

-Infected will no longer try to "ram" through the garage door until it has opened enough for them to pass under (a single common infected may try this, but the rest will take alternate routes/attack from behind)
-Further improved item spawns
-Minor texture fixes
-Fixed spawned melee weapons getting "stuck" together at campaign start if both spawners create a frying pan
-Added regular pistol spawns
-Changed the garage door switch sound to a more matching one

Map 2 (Interior):

-Added more ambient sound effects
-Improved infected navigation near the exterior wall (thanks to Morning for pointing this out)
-Added an additional possible Magnum pistol spawn point

Map 3 (Rooftop Finale):

-Added an additional possible Magnum pistol spawn point
-Improved item spawning
-Improved propane canister spawning
-Added a couple of particle systems + other minor visual additions
-Improved object fade for some important props
-Added and improved ambient sound effects

1.3 Update:

Map 1 (Garage):

-Added a ceiling vent into the long side corridor before the garage door
*This means infected can now get to the survivors from outside even before the panic event is triggered
*It's not 100% idiotproof, however - infected can still try to claw through the unbreakable door
*Special infected tend to make better use of it
-Added a small new room near the start (previously the place had an unusable door)
*Can spawn a single item and/or a melee weapon
-Fixed some places where the infected could not reach human players
-The level can now spawn Tanks/Witches (only one of either, if any)
-Improved item spawns; they're significantly more randomized now
-Fixed one of the lamp posts in the start using the wrong model that made it appear to be on
-Fixed one brush face using the wrong texture in the starting area
-Improved horde spawning; they're now more likely to attack from behind
-Various other small NAV tweaks and improvements

Map 2 (Interior):

-Tweaked horde spawning in a similar way as in the first level

1.2 Update:

Map 2 (Interior):

-Added NAV meshes to a desktop that was missed in the last update
-Also fixed NAV meshes on few other surfaces that bots could not access
-Improved bot navigation further with several minor tweaks and additions
-Added two item spawns to spread loot more evenly throughout the level

Map 3 (Rooftop Finale):

-Made the lawnchairs on the rooftop static to fix an exploit that allowed players to jump up the one-way drop (fixed for real this time)
-Improved the NAV areas on and around the raised platform so that bots can now jump on it (rather than only taking the two ramps on the sides)
-Melee spawns in this level can now include crowbars
-Some other minor NAV tweaks and fixes