A crucial note for the "new" part of your search: as of the first half of 2026, the official website summertimesaga.com/download offers two primary versions: the stable legacy version and the latest preview build of the Tech Update (v21.0.0-wip.7164 or newer). To get Summertime Saga 0.20.16 :
Go back, open the phone again, go to Settings, and select "Main Menu" to activate. The Future: Toward the Tech Update
If you see a post claiming “v0.21.0 for Windows” or “newer than 0.20.16” – it’s fake. The dev team is still working on the Tech Update, and no public build beyond 0.20.16 exists yet.