If you deem it to be solicitor-client privilege, so be it, but internal correspondence certainly isn't all solicitor-client privilege. It's any internal correspondence, advice, or opinions that you're able to disclose, absent solicitor-client privilege, for Apple Canada or its parent U.S. company with respect to whether the slowed performance issue associated with the update should be disclosed.
On March 1st, 2018. See this statement in context.