Ok I resolved the issue myself with help of some apple help articles. After upgrade to Itunes 12.3 the apple mobile device USB Driver was not visible in device manager under USB devices. I followed the steps in this article: iPhone, iPad, or iPod not recognized in iTunes for Windows - Apple Support
Specifically the section "If the Apple Mobile Device USB Driver is not Listed": (there is not updates yet for Windows 10, so the instructions are a little different).
I followed the portion where you right click the apple iphone entry in device manager (was listed under Portable Devices). I right clicked the apple iphone and update driver and followed their instructions as noted below.
Browse to folder C:\Program Files\Common Files\Apple\Mobile Device Support\Drivers.
Double-click the "usbaapl" file. (This file will be called "usbaapl64" if you have a 64-bit version of Windows. If you don't see "usbaapl64" here, or if there is no Drivers folder, look in C:\Program Files (x86)\Common Files\Apple\Mobile Device Support\Drivers. instead).
Click OK in the "Install from Disk" dialog.
Click Next and finish the driver-installation steps. Open iTunes to verify that the device is recognized properly.
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After completing the above immediately the Apple Mobile Device USB Device showed under USB in device manager and itunes picked up the iphone and started syncing (my iphone was already plugged in and itunes was opened).
Regards,
Gaurav