Nintendo has announced that the highly-anticipated system update version 6.0.0 will be available for Nintendo Switch on September 18, the same day Nintendo Switch Online goes into effect. In addition, you won’t be able to unlink your Nintendo Account from your user profile after Nintendo Switch system update version 6.0.0 has been applied. Nintendo has sent the following email to Nintendo Account holders:
Important information about your Nintendo Account
On 9/18, your Nintendo Switch will be receiving a system update, version 6.0.0. Afterwards, it will no longer be possible to unlink your Nintendo Account from your Nintendo Switch user profile. Prior to this change, you should verify that your Nintendo Account or your child’s Nintendo Account is linked to the correct user profile.
For example, please confirm that the parent’s or legal guardian’s Nintendo Switch user profile is linked to the parent’s or guardian’s Nintendo Account, and that the child’s Nintendo Switch user profile is linked to his or her child account.
By ensuring that your Nintendo Account is linked to the correct user profile, you will be able to appropriately manage your save data, Nintendo Switch Online membership, and Nintendo eShop content.
Source: Nintendo of America