Silence from Most U.S. Carriers
If you live in the United States, don't expect carriers to be as open with their plans for Android 6.0.1 Marshmallow.
While international carriers like to help set consumer expectations, U.S. carriers don't like to set any expectations at all. Outside of T-Mobile, U.S. carriers are typically silent on Android update release dates, change logs and other important details.
If you live in the United States and own a Galaxy phone or tablet, you should expect to get your information from leaks rather than carriers themselves. You'll probably find out about most updates on the day they start rolling out.