US Patent 10002236 Controlling use of shared content items based on client device

User accounts can be linked together to form a group of linked user accounts that can access content items assigned to the other user accounts in the group. A user can download content items assigned to their user account, as well as shared content items assigned to one of the other user accounts in the group of linked user accounts. Use of shared content items can be restricted to client devices running specified versions of an operating system. The key ID tagged to a shared content item can be altered such that the key ID no longer correctly identifies the corresponding DRM key that enables use of the shared content item. Client devices authorized to use shared content items can be configured to recognize that a content item is a shared content item and generate the original key ID form the altered key ID.