Today, Apple pushed out the iOS 4.2.6 update via iTunes for the Verizon iPhone 4. The update coincides with the official launch of the Verizon iPhone 4, and addresses a minor issue with the Personal Hotspot feature where the iPhone could show inaccurate usage information for hotspot data. Some Verizon iPhones have shipped with 4.2.6 pre-installed, so very few if any customers need to worry about taking the time to update their device.
My guess is that the release was merely pushed out so that owners of the Verizon iPhone are able to restore their phones if necessary.