2.0.0.0

• Release patch
• Infinite stumble glitch for skipping Swamp map 1 event (patched in the first update)
• Infinite stumble has other applications, the main relevant one being a backup for skipping the event on Quarter
• Used for Main Campaigns solo, and any of the Main Campaigns solo ILs
• First half of Mall is harder than 2.0.0.9 and later - see difference here
• SI limit varies by how far you are into the campaign and difficulty - see this spreadsheet for details
• For campaigns with 5 maps, when playing on easy, the SI limit is 1 for the first three maps, and 2 for maps 4 and 5
• For campaigns with 4 maps, when playing on easy, the SI limit is 1 for the first two maps, and 2 for maps 3 and 4
• Expert always has a limit of 3 regardless of map

2.0.0.8

• Used before 2.0.0.0 was accessible/available/working, no longer relevant.

2.0.1.1

• Used for Dead Center solo due to having the rebalanced (easier) mall script and still having SI limit dependent on map (this means Hotel and Streets have a SI limit of 1 on easy, rather than the static 2 in later versions).

2.0.1.2

• Fastest for Passing solo as you can skip starting the map 2 event, and you can skip the finale elevator ride
• Starting in this version, the SI limit no longer varies by difficulty and map, instead it is always a static 2

2.0.2.7

• Mainly useful for Passing co-op, first version we use where warp mechanics change to allow omniwarping (see co-op basics guide)
• Last version we use that allows you to deal collateral damage to bots/teammates
• First version we use that has cl_viewmodelfovsurvivor unhidden
• Preferred by some for ILs that are part of Main Campaigns due to adjustable viewmodel FOV, but this version is not viable for Swamp Fever due to no infinite stumble, and is also technically harder due to having 2 SI on maps where there would only be 1 on easy in versions older than 2.0.1.2 (see spreadsheet linked above)
• (unconfirmed) may have a higher risk of co-op desync bug that makes boosting other player(s) impossible until rejoining
• Over the course of a Main Campaigns co-op run, loads are about ~2 minutes faster than in 2.0.4.5

2.0.4.5

• Best for No Mercy solo/co-op
• Mainly used for Main Campaigns co-op
• Over the course of a Main Campaigns co-op run, loads are about ~2 minutes slower than in 2.0.2.7
• Last version we use with unlimited votes/no vote cooldown (vote cooldown was added in 2.0.5.0)

2.0.7.5

• Only used for Dead Air solo/co-op, Cold Stream solo

2.0.9.1

• Mainly used for All Campaigns Legacy solo/co-op
• First version with 13 campaigns added to the game
• Also used for ILs of Crash Course solo/co-op, Death Toll solo/co-op, Blood Harvest solo/co-op, Cold Stream co-op

2.1.4.7*

• Applies to any PC run that was done on the latest version of the game prior to the TLS update on the leaderboard (2.1.3.x-2.1.5.5)
• Any run done after TLS update released (September 24th 2020) that is labeled as 2.1.4.7 is actually done on version 2.1.4.7
• 2.1.4.7 is one of the last versions with the exploit that prevents death cameras from playing while holding down push-to-talk ingame - this was patched some time before 2.1.5.5
• Best for Sacrifice solo (co-op can be run on 2.0.4.5-2.1.5.5, doesn't matter)
• Console runs labeled as 2.1.4.7 are not actually 2.1.4.7 - they are a weird mix of versions (pre-2.0.9.1 Carnival finale map, but has other attributes that tie it to approximately ~2.1.0.7 or so). Console also has no vote cooldown on any version.

2.2.0.3

• Last version with director_stop exploit in TLS finale
• Can stand on gas cans when they first spawn which allows for an easy common jump on the No Mercy generator event
• Best for TLS co-op ILs, and All Campaigns co-op
• Used to be ideal for All Campaigns Solo until 2.2.2.8 released

2.2.2.7*

• This version entry applies to any run done on version 2.2.0.4-2.2.2.7 (all pretty much functionally identical for a speedrun)
• RocketDude mushroom overhaul in 2.2.0.8
• FOV slider added in version 2.2.1.3 (June 15th, 2021 update)
• Water slowdown removed in original L4D1 campaigns in 2.2.1.3, but reverted on July 8th, 2021 update

Newest (2.2.2.8+)

• This applies to any run done on version 2.2.2.8 or newer (2.2.2.8 released August 22nd, 2023)
• This update (2.2.2.8) removes the incap trigger on Hard Rain 2 event, making it skippable without bots in solo
• 2.2.2.8 also patched the Cold Stream 2 skip added by TLS (2.2.0.0+) and balanced TLS finale which made it faster/easier in Any Difficulty and Expert Realism