Passive slow increased. E pings enemy champions it spots.

"We're giving Ashe more power in ways that emphasize her unique strengths as a utility marksperson rather than escalating the DPS race."

Passive - Frost Shot

SLOW : 10% - 20% (lvl 1-18) ⇒ 15% - 30% (lvl 1-18)

SLOW CRIT MULTIPLIER : Triple ⇒ Double (slow amount unchanged due to base slow buff)

E - Hawkshot

'Hey' : Hawkshot now pings enemies it spots if your team didn't already have vision of them

'Feathery' : Hawkshot vision trail duration very slightly increased to address a bug where the trail sometimes wouldn't show up on the minimap (vision duration at the destination unchanged)

Bugfixes

'Frosty' : Fixed a bug that made Runaan's Hurricane bolts fired by Q - Ranger's Focus invisible

source: https://oce.leagueoflegends.com/en/news/game-updates/patch/patch-821-notes/