League of Legends Patch 9.18 notes breakdown – Teamfight Tactics edition

Systems

"XP Adjustments Due to the slightly inflated gold from the new loot system, we’ve made some adjustments to how much XP it takes to level. Level 5: 10xp -> 12xp Level 6: 18xp -> 20xp Level 7: 30xp -> 32xp Level 8: 46xp -> 50xp Level 9: 64xp -> 70xp"

So the really interesting part of the experience changes is the Level 5 XP bump. By making it 12 XP, not 10 XP, that means that you will not hit Level 5 at the Krug stage if you only use the experience bump once. That is usually the common point to start spending XP for upgrades to get that extra champion, so you’ll have to spend at least 8 gold to get that bonus XP (potentially making win-streaking, loss-streaking, or Pirate buff more impactful early).

"Champion Tier Drop Rates We’ve made some minor adjustments to how likely which tier champions will appear at a few different levels. We’re hoping these make clearer early, mid, and late game phases. Level 3 by Tier: 65%/ 30%/ 5%/ 0%/ 0% -> 70%/ 25%/ 5%/ 0%/ 0% Level 5 by Tier: 37%/ 35%/ 25%/ 3%/ 0% -> 35%/ 35%/ 25%/ 5%/ 0% Level 6 by Tier: 24.5%/ 35%/ 30%/ 10%/ 0.5% -> 25%/ 35%/ 30%/ 10%/ 0% Level 9 by Tier: 10%/ 15%/ 35%/ 30%/ 10% -> 10%/ 15%/ 33%/ 30%/ 12% All other levels remain the same."

At Level 3 (during the last minion round) you’ll have slightly better odds of getting a Tier 1 (gray) champion than a Tier 2 (green), making it slightly more likely you can find three Tier 1s to build into a 2-star champ). At Level 5, you’ll get slightly better odds of getting a Tier 4 (purple) at the expense of a lower chance for a Tier 1. Level 6, you get a slightly better chance for a Tier 1 but will not get any Tier 5 (gold) champions) and finally at Level 9 you’ll have more Tier 5s but less Tier 3s. The tl;dr of these changes is that early on, you get more Tier 1s, mid game, you get less Tier 1s and now can’t get Tier 5s until Level 7, and at Tier 9 you’ll get more Tier 5s.

"Champion Pool Sizes It’s proven a bit too consistent to get 2-star Tier 3 champions, so we’re shrinking the bag size to reward players who build the path less taken. Tier 3 champions in pool: -> 18"

This probably hurts Demon comps a lot, since two of them (Aatrox and Evelynn) were both very common to get to a 2-star. It also makes getting a 2-star Tier 3 champion (blue) much more impactful, so you should grab pairs of them when you can.

Item Stacking and Clarity

"We took a pass at all the items to ensure that they stack in a sensible way and that we’re informing you when they don’t. Adding copies of items that do not stack will now cause them to bounce off any champion they are placed on. Unique items will be labeled as such in their tooltips. All items listed below are not intended to stack. Youmuu’s Ghostblade Knight’s Vow Frozen Mallet Yuumi Blade of the Ruined King Darkin Phantom Dancer Morellonomicon Red Buff"

Good quality of life change so that you’re not wasting an item on a champion that its passive won’t stack with.