Sirius Canada Customer Service did not know about any changes to the Internet channel offerings when I called them on Tuesday, but they did respond to my email query today indicating the channels have been removed from the Internet stream. They provided no details on which channels were removed.
Internet channels marked "SIR-" are likely affected. In the case of Cinemagic, this station is still being broadcast by XM Canada, a separate company, and this may affect streaming rights by Sirius Canada.
Sirius Canada is at least consistent in their approach to changes in their service. No notification to the customer and no information explaining the changes from the call center for days. They don't appear to implement any communication plan when they make changes.
Bottom line. Sirius Canada customers are now getting fewer Internet channels for their subscription.