Office365 Groups settings are configured using a Settings object and a SettingsTemplate object. Initially, you will not see any Settings objects in your directory. This means your directory is configured with the default settings. To change the default settings, you will need to create a new settings object using a settings template. Settings templates are defined by Microsoft. There are several different settings templates. To configure group settings for your directory, you will use the template named "Group.Unified". To configure group settings on a single group you will use the template named "Group.Unified.Guest". This template is used to manage guest access to a group.
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