From GameWatcher: “League of Legends’ Patch 10.15 is now live on the PBE for a testing period of about two weeks, and taking a first look at its patch notes reveals its release date alongside new champion Lillia, Spirit Bloom skins, and more. What else can we tell you about the next update in the League of Legends 2020 Patch Cycle?
According to Riot’s own patch schedule, League of Legends Patch 10.15’s release date is set for Wednesday, July 22, which is when the changes hit the LoL live servers.”
Source: N4G PC League of Legends Patch 10.15 – Release Date, Lillia, Spirit Blossom Skins, Champion Changes