It’s time to start bringing the power of Office 365 Groups to your classic team sites! The ability to connect an existing SharePoint Online site to a new Office 365 Group is a new Office 365 feature.
Initially, an administrator will be able to use both an API and a PowerShell cmdlet to connect existing SharePoint Online team sites to new Office 365 Groups. In late May, Microsoft will expand this ability to site collection administrators by adding a command to the Settings menu on classic SharePoint Online team sites.
As part of the rollout of these tools, Microsoft is also including a setting that allows Office 365 administrators to control whether or not the feature is available to site collection administrators. This setting will be enabled by default but can be changed by an administrator at any time.
If you would like to allow SharePoint Online site collection administrators to use a command on the Settings menu to connect classic team sites to new Office 365 Groups, then there is nothing you need to do to prepare for this change.
If you don’t want site collection administrators to be able to use a command on the Settings menu to connect classic team sites to Office 365 Groups, you will need to turn off the setting in the admin center. You can change the setting later to enable the feature for site collection administrators.