Overview
We’re going to give you a quick rundown of key points from the latest patch. You can also see how these changes have affected the meta by looking at our Champion Statistics page, which highlights changes in Win Rate between patches.
This is primarily a balanced-focused patch, but it introduces a couple of new things: notably summer skins and a new tool to preview abilities in champion select. You'll be able to hover over champion portraits to see a small video of that champion's playstyle.
For a full breakdown of exactly what has been changed, check out Riot’s official patch notes here.

Ability Previews

Hover over portraits in champion select to preview what champions can do (you can turn this feature off if it's too distracting).
Koeshin's Courtyard
This is now unlocked by default. You will no longer be required to finish Battle of Koeshin in order to play it.
Systems
Baron Nashor no longer has passive health regen -- this means your Smite timings will not be randomly griefed by its health ticking up now. He'll receive 100 base health as compensation.
Champions
Buffs
Kled (Passive dismounted resistances increased.)
Nerfs
Alistar (Base Armor reduced.)
Braum (Base Armor and Armor Growth decreased.)
Corki (Q damage formula adjusted. R damage increased.)
Irelia (Health Regen decreased.)
Master Yi (Q damage reduced for low AD builds.)
Nilah (Base AD increased, Attack Speed Growth decreased.)
Pantheon (Q monster damage decreased.)
Quinn (Q damage decreased.)
Rell (W shield decreased.)
Changed
Bel'Veth (Passive Attack Speed increased at levels 2-18. Q damage to champions decreased.)
Illaoi (Passive damage increased. E adjusted.)
Rek'Sai (Base Armor and Armor Growth decreased. W knock up lockout decreased at higher ranks. E deals adjusted true damage. R adjusted.)