Blitzcrank
Base mana reduced to 240 from 300
Rocket Grab
Mana cost increased to 120 from 110

Cho'Gath
Feral Scream
Silence duration reduced to 1.5/1.75/2/2.25/2.5 seconds from 2/2.25/2.5/2.75/3

Diana
Pale Cascade
Adjusted orbs to better account for enemy model size

Elise
Neurotoxin
Mana cost increased to 80/85/90/95/100 from 60
Cocoon
Mana cost reduced to 50 from 65

Ezreal
These changes are a continuation of our earlier effort to carefully scale back some of Ezreal’s excess power. Although these nerfs affect AP Ezreal, right now we’re focused on stabilizing AD Ezreal. After that we’ll assess the state of AP Ezreal.
Base movement speed reduced to 325 from 330
Rising Spell Force
Duration reduced to 5 seconds from 6
Trueshot Barrage
Damage falloff per target hit increased to 10% from 8%

Heimerdinger
Though these aren’t all the Heimerdinger changes we’d eventually like to do, these are some quality of life adjustments that should help smooth out Heimer’s current gameplay.
H-28G Evolution Turrets
Now displays timer of when Heimerdinger will get his next ammo charge
Turrets will now attempt to prioritize enemies hit by Heimerdinger’s basic attacks or his CH-1 Concussion Grenade
UPGRADE!!!
Cast time removed

Katarina
These changes are focused on once again increasing the risk of Katarina’s gameplay by forcing her to build more offensive stats and focus on pulling off well-timed Death Lotuses.
Bouncing Blades
Initial damage reduced to 60/85/110/135/160 from 60/90/120/150/180
Shunpo
Damage reduction duration reduced to 1.5 seconds from 3
Death Lotus
Total ability power ratio increased to 2.0 from 1.75

Kennen
Slicing Maelstrom
No longer has an energy cost

Lulu
Pix, Faerie Companion
Damage adjusted to 9-105 from 15-87

Master Yi
Meditate
Total heal amount increased to 200/350/500/650/800 from 140/280/420/560/700
Total ability power ratio reduced to 2.0 from 4.0
Mana cost reduced to 50/65/80/95/110 from 70/80/90/100/110

Miss Fortune
Bullet Time
Bonus attack damage ratio reduced to 0.35 from 0.45
Targeting cone is now attached to Miss Fortune

Nasus
Nasus now gains double the bonus from Siphoning Strike when it’s used to kill more significant (“large”) targets such as enemy champions, cannon minions, the giant wolf or even Baron Nashor. This change reinforces the game’s general reward structure, wherein more important units provide additional rewards.
Siphoning Strike
Permanent damage bonus is now doubled to 6 when killing a champion, large minion or large monster

Nunu
These changes are focused on forcing Nunu to play more actively in his support role by reducing the power he passively contributes to his allies.
Base movement speed increased to 350 from 340
Blood Boil
Duration reduced to 12 seconds from 15
Attack speed bonus reduced to 25/30/35/40/45% from 25/35/45/55/65%
Movement speed bonus reduced to 8/9/10/11/12% from 11/12/13/14/15%

Olaf
Undertow
Slow now fades over the duration
Vicious Strikes
Cooldown increased to 16 seconds from 12
Ragnarok
No longer passively grants bonus armor penetration
Now only grants bonus armor penetration while active

Shaco
Deceive
Range reduced to 400 from 500
Two-Shiv Poison
Slow reduced at earlier ranks to 10/15/20/25/30% from 20/22.5/25/27.5/30%

Shen
Ki Strike
Cooldown reduction per attack reduced to 1 second from 1.5
Cooldown reduction per attack while Feint is active reduced to 2 seconds from 3

Sion
Sion now receives twice the bonus stats from Enrage when he uses it to kill more significant (“large”) targets such as enemy champions, cannon minions, the giant wolf or even Baron Nashor. This change reinforces the game’s general reward structure, wherein more important units provide additional rewards.
Enrage
Permanent max health bonus is now doubled to 2/3/4/5/6 upon killing a champion, large minion or large monster

Tristana
Rapid Fire
Mana cost reduced to 50 from 80
Explosive Shot
Damage increased to 110/150/190/230/270 from 110/140/170/200/230

Tryndamere
Base Attack Speed increased to 0.670 from 0.644
Fury decay now begins after 8 seconds of being out of combat from 5 seconds

Veigar
Veigar now receives twice the bonus stats from Baleful Strike when he uses it to kill more significant (“large”) targets such as enemy champions, cannon minions, the giant wolf or even Baron Nashor. This change reinforces the game’s general reward structure, wherein more important units provide additional rewards.
Baleful Strike
Permanent ability power gain is now doubled to 2 when killing a champion, large minion, or large monster

Vi
Updated Recommended Items
Vault Breaker
Fixed a bug where Vault Breaker's area of effect was inconsistent at the end area of the dash
Fixed a bug where Improved Recall was refunding Vault Breaker's cooldown and mana cost
Excessive Force
Fixed a bug where Excessive Force could fire multiple times if used on an invulnerable target or while blinded

Volibear
Volibear’s base attack speed was below average for an attack-based melee champion. This change helps address this deficiency and helps him clear the jungle.
Base attack speed increased to 0.658 from 0.625

Items

Seeker's Armguard (New Item)
Recipe: Cloth Armor + Cloth Armor + Amplifying Tome + 125 gold = 1160 gold
+30 armor
+25 ability power
Unique passive: Kills grant 0.5 bonus armor and ability power. This bonus stacks up to 30 times.

Zhonya's Hourglass
Recipe changed: Seeker's Armguard + Needlessly Large Rod + 650 gold = 3410 gold (from 3100)
Ability Power increased to 120 from 100

Sightstone
These changes are to reduce the excessive amount of early vision teams can acquire with little cost. This should create more opportunities to gank and reward counter play, especially for junglers.
Recipe changed: Ruby Crystal + 475 gold = 950 gold (from 700)
Health increased to 180 from 100
Gold reward for Sightstone wards increased to 25 from 10

Ruby Sightstone
These changes are to reduce the excessive amount of early vision teams can acquire with little cost. This should create more opportunities to gank and reward counter play, especially for junglers.
Total cost increased to 1550 gold from 1300
Health increased to 360 from 300
Gold reward for Ruby Sightstone wards increased to 25 from 10

Giant's Belt
Health reduced to 380 from 400

Warmog's Armor
Recipe changed: Giant's Belt + Ruby Crystal + Rejuvenation Bead + Rejuvenation Bead = 2830 gold (from 2650)

Sunfire Cape
Combine cost increased to 930 gold from 780 (total cost increased to 2650 gold from 2500)

Fiendish Codex
This change allows Fiendish Codex and its various build paths to be more versatile and universally attractive for ability power champions.
Faerie Charm removed from recipe
Total cost is now 820 gold from 1000
No longer grants any mana regen

Nashor's Tooth
Combine cost reduced to 200 gold from 250 (total cost reduced to 2270 gold from 2500)
No longer grants any mana regen

Banner of Command
Recipe changed: Fiendish Codex + Emblem of Valor + 890 gold = 2360 gold (from 2400)

Deathfire Grasp
Recipe changed: Fiendish Codex + Needlessly Large Rod + 880 gold = 3300 gold (from 3000)
Ability power increased to 120 from 100

Morellonomicon
Recipe changed: Faerie Charm + Fiendish Codex + Kage's Lucky Pick + 435 gold = 2200 gold

Athene's Unholy Grail
Combine cost reduced to 900 from 920 (total cost reduced to 2600 gold from 2800)

The Bloodthirster
Combine cost increased to 850 gold from 650 (total cost increased to 3200 gold from 3000)

The Black Cleaver
We are now fairly comfortable with Black Cleaver’s strategic niche, but we want to scale back some excess power.
Health reduced to 200 from 300
Maximum stacks increased to 5 from 4
Armor reduction per stack reduced to 5% from 6%
Fixed a bug where spells were applying more reduction than intended

Trinity Force
Combine cost reduced to 3 gold from 300 (total cost reduced to 3903 gold from 4200)

Spirit Stone
Combine cost reduced to 40 gold from 140 (total cost reduced to 700 gold from 800)

Spirit of the Spectral Wraith
Combine cost reduced to 100 gold from 400 (total cost reduced to 2000 gold from 2400)

Frozen Heart
Combine cost reduced to 400 gold from 500 (total cost reduced to 3000 gold from 3100)

Doran's Shield
Health regen per 5 seconds increased to 8 from 5

Matchmaking
The matchmaking system will now take into account matchmaking rating and number of wins in the player's current queue when creating matches

General
We've made database upgrades which have cleared displayed match history in player profiles. All stats are still stored, but your previous 10 games will not show up.
Tenacity now appears on the character sheet as a stat.
All champions with abilities that reduce the duration of disabling effects now gain tenacity instead.
e.g. Singed, Trundle, Irelia, Garen, etc.
Champion tenacity stacks with item tenacity, mastery tenacity and cleanse.
Fixed a bug where Rengar and Kha'zix "On The Hunt" quest might fail to activate when Kha'zix was dead.
Fixed a bug where chat messages from Anivia would display the incorrect champion name while she was in egg form.
Inhibitors and turrets now have kill callouts.

Co-op vs. AI:
Bots will occasionally chat at the beginning and end of games
Added Jarvan IV bot to all maps
Improved retreat logic for bots with dashes.