Minori on Twitter took a picture of the back of "Hakuoki Shinkai: Fuukaden," with some text that translates to “Compatible with Save Data Cloud Backup of Nintendo Switch Online.”

薄桜鬼買ってきたんだが、気になる表記が。『｢NintendoSwitchOnline｣の｢セーブデータお預かり｣に対応しています。』か… pic.twitter.com/RzeQxqZIpt

— みのり (@MIN428) September 6, 2018

Additionally, the Nintendo UK website for Switch Online has been updated with this:

https://www.nintendo.co.uk/Nintendo-Switch/Nintendo-Switch-Online/Nintendo-Switch-Online-1183143.html

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This is technically all a rumor, but signs are pointing towards confirmed, guess we'll find out during the upcoming Nintendo Direct. :/

Isnt that already confirmed. I could swear Ive heard that before.

It's a brand new and exciting technology. You can't expect them to get it right on their first try.

I'm not sure but I'm gonna assume there are some rare outliers on steam that don't work either. Then again, it's a pc, there are endless possibilities to back up your saves forever and for free.

Yes it was, but seems some people didnt want to belive in that.  :D

I'm guessing games like NBA with 5gb save files won't support it.

That's what I was thinking.

Also remember that any online game had save file limitations on the Wii.
It is something that they have done before, keeping a save file locked into hardware.