I get this today.
Rich, your Chevrolet Silverado is due for a software update that must be performed at a dealership. This update will provide software improvements and optimize your vehicle for future over-the-air updates. Once completed, your vehicle will have up-to-date technology, including the latest infotainment features, performance enhancements and more.
Called the dealer and they tell me the update was the one that happened a few weeks ago and has been completed. This is second time I have got an email from GM for an update that has already been done.
Anyone else have his issue? I have yet to get an update notice on my app either. Just email.