Google has released the list of products available for Marshmallow 6.0 and will not take the blame or responsibility for any service provider that doesn't offer the customer service and upgrades that everyone is entitled to receive. A list of service provider that neglects that last upgrade is requested by Google and all consumers needs to know the service providers like Fido that is failing in the customer service and keeping the customers updated.
Updates are the responsibility of the manufacturer not Fido. Some are quick ( HTC) and some are slow ( Samsung) while others don't update anything but their newest devices. I received marshmallow before Xmas and knowing HTC is dedicated to updating their devices within 90 days of official release was one of the many reasons I went with an HTC.
You didn't mention which device you have, but it should be pointed out that the manufacturer needs to provide the update in the first place. It's possible that there's no update for Fido to approve at this time.
