Google+ is now available for Google Apps accounts.

I logged in today on Google+ and instead of the usual inscription “Google+ is not yet available for Google Apps” I found a message saying that “Google+ is not available for your organization”. I went into the management of my domain, brought the switch to the “On” state and got access to Google+ from an account linked to my own domain.

EDIT: In the comments they write that the service connection is not available for all domains yet. Some have encountered a problem when the corresponding setting is already available, but its state is not saved.