SmartSwitch, especially when coming from devices more than 3 years older than when your current device was released, can sometimes create some unusual issues. If you brought over contacts and text messages only. That's nothing to worry about. It's when apps and user settings are transfered when you sometimes get issues.
Updates are staggered though and usually in 3 waves. You have the first wave, which is usually a small amount of devices on a single carrier. A couple of weeks later as long as no major issues are found. A push to more devices on multiple carriers happens. After another 2 weeks, you usually get a push to all devices. If the carrier wants to radio firmware or carrier settings update included. That can delay an update push for that carrier because Samsung and other manufacturers have to integrate these into the update before it gets pushed to devices on that specific carrier.
