Update 9/13/2018: Nintendo has announced the Switch's 6.0.0 system update will arrive alongside the Online Service activation on September 18.
The update will be pushed out to users at 5pm PT / 8pm ET (that's September 19 at 1am UK / 10am AEST). The Nintendo eShop will undergo maintenance for 3 hours after the update is released.
While little is known about what improvements will come with 6.0.0, it will likely be responsible for enabling cloud saving and other new online features.
Switch users have also been informed that, following 6.0.0, Switch User Accounts will be tied permanently to the Nintendo Account they're currently tied to. Make sure you've linked the correct accounts before that date.
Nintendo has revealed that its upcoming Nintendo Switch Online service will be launching next Tuesday, September 18, and will be arriving with a 7-day free trial from the Nintendo eShop.
Announced via Twitter, Nintendo confirmed that its paid Nintendo Switch Online Service will be launching next week and that more information will be revealed at tomorrow's 35-minute Nintendo Direct that will focus on upcoming Switch and 3DS titles.
Nintendo previously said that its online service would be launching in the "second half of September" and would cost significantly cheaper than Xbox Live Gold and PlayStation Plus.
There will be three options of purchase, including a 1-month membership that will cost $3.99 USD, a 3-month that will be $7.99 USD, and a 12-month subscription that will be $19.99 USD.
In addition to the ability to play online games with friends, which had previously been free, subscribers will gain access to 20 NES games at launch, including Super Mario Bros., The Legend of Zelda, and Super Mario Bros. 3.
Another long requested feature, cloud saves, will become available with this new service although it appears not all games will be taking advantage of the feature.
Many more answers will be given tomorrow at the Nintendo Direct, which was delayed due to an earthquake in Hokkaido, Japan, and with the launch of this service less than a week away, we should be in for a good show!
Adam Bankhurst is a news writer for IGN who is excited to see what the Nintendo Switch Online service is all about and hopes they at least tease SNES games and Super Mario Sunshine Gamecube Classic. You can follow him on Twitter @AdamBankhurst.